load cell digitizing unit type ldu 78€¦ · command set. so you can connect up to 32 sg...

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Ideas in Measuring ..TECHNIQUES LIMITED

LDU78.1 Manual Issue 1g

Load Cell Digitizing Unit Type LDU 78.1

MANUAL

Firmware Version 78.183 v2.XX



1 INTRODUCTION & SPECIFICATIONS 3

2 COMMUNICATIONS & GETTING STARTED 4

2.1 Serial Interface 42.2 Command Language 42.3 Setup baud rate / device address 52.4 Getting Started 5

3 HARDWARE & WIRING 6

3.1 Load Cell Connections 73.2 Power Connections 73.3 Logic Inputs and Logic Outputs 73.4 Communication Connections 7

4 COMMANDS OVERVIEW 10

5 COMMANDS 13

5.1 System diagnostic Commands - ID, IV, IS, SR, RS 145.2 Check Weigher Set Up Commands - SD, MT, GA, TE, TL, TR, RW, TT, HT,

TW, TI, DT, TS 165.3 Calibration Commands - CE, CI, CM n, DS, DP, CZ, CG, ZT, FD, IZ, ZR, ZI,

WT, CS, TM, TN 205.4 Motion detection Commands - NR, NT 255.5 Filter setting Commands - FM, FL, UR 265.6 Set Zero/Tare and Reset Zero/Tare Commands - SZ, RZ, ST, RT, ZA, SP 285.7 Output Commands - GG, GN, GT, GS, GW, GA, GL, OF 305.8 Auto-transmit Commands - SG, SN, SA, SW, SL, SX 335.9 Commands for external I/O control - IN, IO, IM, TC 355.10 Setpoint Commands - Sn, Hn, An 375.11 Communication setup Commands - AD, CL, BR, DX, OP, TD 395.12 Save calibration, setup & setpoint parameters Commands - CS, WP, SS, PI, GI 41

6 CALIBRATION PROCEDURE 42

7 USE IN “APPROVED” APPLICATIONS 43

8 SOFTWARE (FIRMWARE) DOWNLOADS 44

8.1 Firmware updates for the LDU XX.X series 44

9 UNIT ADAPTOR CONNECTION DETAIL 459.1 UA 77.1 Unit Adaptor with built-in RS422 to RS232 converter 459.2 UA73.2 Standard Unit Adaptor 46

10 USB to RS422/485 CONVERTER WIRING (Multi-drop application) 47


Page 3 LDU78.1 Manual Issue 1g

All dimensions in mm. Dimensions and specifications are subject to change without notice.

1 INTRODUCTION & SPECIFICATIONS

The model LDU 78.1 is a precise, high speed digital amplifier for weighing and force measurements applications which use strain gauge (SG) based sensors. The LDU 78.1 can be used in legal for trade, as well as industrial applications. The device features full multi-drop communication capability and can be programmed using the straight forward ASCII command set.

The LDU XX.X series and the DAS72.1 amplifier with on-board digital display, use the same command set. So you can connect up to 32 SG amplifiers of either the LDU X.XX series or the DAS72.1 types onto a single RS 485 bus.

The LDU 78.1 with its high precision 18 bit A to D converter and a fast internal sample rate of up to 2400 measurements/second, is particularly suitable for high speed dynamic measurements and control.

Technical Specifications of the LDU 78.1:

Accuracy Class

EU Type approved

Linearity

Load Cell Excitation

Load Cell Drive Capability

Analogue Input Range

Minimum input per vsi

Resolution

Conversion rate

Digital filter IIR LP

Digital filter FIR LP

Calibration

Computer Interface

Weighing functions

Inputs

Outputs

Temperature effects

Temperature range

Enclosure

Dimensions

Power supply

Options

EMC/Approvals

III

R76 10000 Divisions

<0.002% Full Scale

5 V DC

Input impedance 80-2000 Ohms (12-14V DC Supply), 6-wire technique

Input Impedance 350-5000 Ohms (14-24V DC Supply), 6-wire technique

±2.2 mV/V (bipolar, for push/pull weighing or tension/compression forces)

50nV per interval non-approved, 0.3µV per interval approved

Internal max 260,000 counts, external max ± 99,999 counts

Up to 600 measurements per second

0.25Hz -18Hz (i.e.40 dB/decade) selectable in 8 steps

2.5Hz - 19.7Hz selectable in 8 steps

Software calibration and set up

RS485 or RS422 full duplex, 9600 ... 115200 Baud; up to 32 devices on a bus.

Zero, gross, tare, net, filter etc.

2 opto-isolated inputs, 10-30 VDC max. 3 mA

2 open collector outputs, <30 V DC

On zero:<7 ppm/°K

On span:<6 ppm/°K

-15°C to +50°C (compensated); -30°C to +70°C (storage)

Tin plated steel enclosure sealed to IP 40

82 x 31 x 6 mm, weight approx. 30 g; with adaptor board 91 x 41 x 12 mm

approx. 50 g

12 ... 24 V DC ±10%, <100mA, not galvanically isolated.

Adaptor board UA73.2 (passive) or UA77.1 (RS422 to RS232)

2004/22/EC MID Class E2 (Industrial Locations) passed



1 INTRODUCTION & SPECIFICATIONS 3

2 COMMUNICATIONS & GETTING STARTED 4

2.1 Serial Interface 42.2 Command Language 42.3 Setup baud rate / device address 52.4 Getting Started 5

3 HARDWARE & WIRING 6

3.1 Load Cell Connections 73.2 Power Connections 73.3 Logic Inputs and Logic Outputs 73.4 Communication Connections 7

4 COMMANDS OVERVIEW 10

5 COMMANDS 13

5.1 System diagnostic Commands - ID, IV, IS, SR, RS 145.2 Check Weigher Set Up Commands - SD, MT, GA, TE, TL, TR, RW, TT, HT,

TW, TI, DT, TS 165.3 Calibration Commands - CE, CI, CM n, DS, DP, CZ, CG, ZT, FD, IZ, ZR, ZI,

WT, CS, TM, TN 205.4 Motion detection Commands - NR, NT 255.5 Filter setting Commands - FM, FL, UR 265.6 Set Zero/Tare and Reset Zero/Tare Commands - SZ, RZ, ST, RT, ZA, SP 285.7 Output Commands - GG, GN, GT, GS, GW, GA, GL, OF 305.8 Auto-transmit Commands - SG, SN, SA, SW, SL, SX 335.9 Commands for external I/O control - IN, IO, IM, TC 355.10 Setpoint Commands - Sn, Hn, An 375.11 Communication setup Commands - AD, CL, BR, DX, OP, TD 395.12 Save calibration, setup & setpoint parameters Commands - CS, WP, SS, PI, GI 41

6 CALIBRATION PROCEDURE 42

7 USE IN “APPROVED” APPLICATIONS 43

8 SOFTWARE (FIRMWARE) DOWNLOADS 44

8.1 Firmware updates for the LDU XX.X series 44

9 UNIT ADAPTOR CONNECTION DETAIL 459.1 UA 77.1 Unit Adaptor with built-in RS422 to RS232 converter 459.2 UA73.2 Standard Unit Adaptor 46

10 USB to RS422/485 CONVERTER WIRING (Multi-drop application) 47



All dimensions in mm. Dimensions and specifications are subject to change without notice.

1 INTRODUCTION & SPECIFICATIONS

The model LDU 78.1 is a precise, high speed digital amplifier for weighing and force measurements applications which use strain gauge (SG) based sensors. The LDU 78.1 can be used in legal for trade, as well as industrial applications. The device features full multi-drop communication capability and can be programmed using the straight forward ASCII command set.

The LDU XX.X series and the DAS72.1 amplifier with on-board digital display, use the same command set. So you can connect up to 32 SG amplifiers of either the LDU X.XX series or the DAS72.1 types onto a single RS 485 bus.

The LDU 78.1 with its high precision 18 bit A to D converter and a fast internal sample rate of up to 2400 measurements/second, is particularly suitable for high speed dynamic measurements and control.

Technical Specifications of the LDU 78.1:

Accuracy Class

EU Type approved

Linearity

Load Cell Excitation

Load Cell Drive Capability

Analogue Input Range

Minimum input per vsi

Resolution

Conversion rate

Digital filter IIR LP

Digital filter FIR LP

Calibration

Computer Interface

Weighing functions

Inputs

Outputs

Temperature effects

Temperature range

Enclosure

Dimensions

Power supply

Options

EMC/Approvals

III

R76 10000 Divisions

<0.002% Full Scale

5 V DC

Input impedance 80-2000 Ohms (12-14V DC Supply), 6-wire technique

Input Impedance 350-5000 Ohms (14-24V DC Supply), 6-wire technique

±2.2 mV/V (bipolar, for push/pull weighing or tension/compression forces)

50nV per interval non-approved, 0.3µV per interval approved

Internal max 260,000 counts, external max ± 99,999 counts

Up to 600 measurements per second

0.25Hz -18Hz (i.e.40 dB/decade) selectable in 8 steps

2.5Hz - 19.7Hz selectable in 8 steps

Software calibration and set up

RS485 or RS422 full duplex, 9600 ... 115200 Baud; up to 32 devices on a bus.

Zero, gross, tare, net, filter etc.

2 opto-isolated inputs, 10-30 VDC max. 3 mA

2 open collector outputs, <30 V DC

On zero:<7 ppm/°K

On span:<6 ppm/°K

-15°C to +50°C (compensated); -30°C to +70°C (storage)

Tin plated steel enclosure sealed to IP 40

82 x 31 x 6 mm, weight approx. 30 g; with adaptor board 91 x 41 x 12 mm

approx. 50 g

12 ... 24 V DC ±10%, <100mA, not galvanically isolated.

Adaptor board UA73.2 (passive) or UA77.1 (RS422 to RS232)

2004/22/EC MID Class E2 (Industrial Locations) passed



The command OP_2 opens the communication channel to device #2 and closes communication with device #1. Now device #2 acknowledges that it is active (OK) and responds to any commands on the bus. Communication with device #2 will be closed by another OP command (for another device on the bus e.g. OP_5) or by the close command e.g. CL_2.

Each OP_X command implies a CL command to all other devices on the bus except #X. This makes the address structure easier and improves system performance.

2 COMMUNICATIONS & GETTING STARTED

2.1 Serial Interface

Communication with the LDU 78.1 is via the RS422/RS485 port. The data format is the familiar 8/N/1 structure (8 data bits, no parity, 1 stop bit). The LDU 78.1 can communicate at the following baud rates: 9600, 19200, 38400, 57600, 115200 baud.

RS422

! Connection using a 4 wire technique.

! Point to Point connection for single units or multidrop connection for up to 32 LDUs on a bus.

! Full duplex (DX=1)

RS485

! Connection using 2 wire techniques! Multi-drop connection possible with up to 32 LDU XX.X on a bus.! Half duplex only (DX=0).

(RS232)

! An optional adaptor board model UA77.1 is available, which has a built-in RS422 to RS232 converter for point to point connection of single units.

(USB)

! An optional external adaptor model USB485i is available, which converts RS422/485 to USB for point to point or multi-drop connections of LDUs to a PC.

The command set for the LDU XX.X series is based on a simple ASCII format. This consists of a 2 capital letter code which enables the user to setup the device, get results or check parameters.

Example:

An LDU XX.X with the address or channel number 1 is connected via the RS422 port to a bus system. You want to get the net weight from this device. In this manual a space is represented by “_” and Enter (CR/LF) by “¿”

2.2 Command Language

Master (PC / PLC) sends Slave (LDU XX.X) responds Status

OP_1¿

GN¿

OK

N+123.45

Device number 1 ready

Open Device number 1

Net weight value with sign & decimal point

Get Net weight value



2.3 Setup Baud rate / Device Address

The factory default baud rate is 9600 baud. The factory default device address is 0. Under normal circumstances the baud rate can be changed or viewed using the BR command (Page 37). Similarly, the device address can be changed or viewed using the AD command (Page 37). If however you do not know the device baud rate or address, the LDU can be put into a special configuration mode which allows the baud rate and device address to be reset. On the under side of the LDU PCB are a set of special solder pads (SW3) - See diagram on page 6. If these solder pads are bridged (shorted together) then the LDU will enter the special configuration mode on power up.

Baud Rate (In Configuration Mode)

With SW3 pads bridged, the LDU XX.X will enter a special baud rate search mode on power up. This involves the LDU waiting for a space character (0x20) to be received. The time duration of this character is measured by the LDU and its baud rate will be set accordingly - i.e. the baud rate of the terminal sending the space character will be used by the LDU. The factory default baud rate is 9600 baud.

Address Settings (In Configuration Mode)

With SW3 pads bridged, the LDU XX.X will enter a special configuration mode on power up. It is possible to set the network address of the device using the AD command. (Address range between 0 and 255). Setting the address to 0 will set it into continuously active mode, where the device will listen and respond to any command on the bus without the need for an OP xxx command.Factory default: Address 0

2.4 Getting Started

You will require a:

! PC or PLC with either a RS422 or RS485 communication port ! If you are using a PC or PLC with an RS232 port, you will require a RS422 to RS232 converter (optional unit adaptor UA77.1)! If you are using a PC or PLC with an USB port, you will require a RS422/485 to USB converter (optional Model USB485i)! Interconnecting cabling - See the wiring diagram on Page 6! A load cell / scale with test weights or a load cell simulator! A 12-24 V DC power supply capable of delivering approximately 100mA for each LDU and load cell! One or more LDU 78.1! The DOP 4 software*

Refer to the wiring diagram on Page 6

!*The DOP 4 software with graphical user interface and oscilloscope function is now available for Windows PCs. Download the latest version of the DOP 4 software from http://www.haubac.com/haubac.asp?p1=167 together with Quick Start and Users Manuals



The load cell(s) are connected to pins 0 to 6 of the LDU78.1. Pins 1 & 6 provide excitation (5 V DC) to the load cell circuit, pin 1 being positive excitation (+Exc) and pin 6 negative excitation (-Exc).Pins 3 & 4 are the signal inputs to the LDU78.1 from the load cell circuit, pin 3 being the positive signal (+Sig) and pin 4 being the negative signal (-Sig).Pins 2 & 5 are the Sense connections for the LDU78.1, pin 2 being the positive sense (+Sen) and pin 5 the negative sense (-Sen). If your load cell has 6 wires ( 2 for Excitation, 2 for Signal and 2 for Sense) the sense connections provide the LDU78.1 with the voltage that reached the load cell(s) as opposed to the voltage that was sent. This enables the LDU 78.1 to correct for voltage drops on long cables.If your load cell only has 4 wires you will need to link the positive excitation (+Exc) pin (Pin 1) and the positive sense (+Sen) pin (Pin 2) and similarly the negative excitation (-Exc) pin (Pin 6) and the negative sense (-Sen) pin (Pin 5). This can be achieved simply by solder bridging pads SW1 and SW2 on the underside of the LDU 78.1 pcb. (See diagram on )Pin 0 provides a ground connection for the load cell cable screen or drain wire.

Power is provided to the LDU 78.1 via pins 18 & 19, pin 18 being the positive supply (Pwr) 12 - 24 VDC and pin 19 being the power supply ground (Gnd) 0 V.

3.1 Load Cell Connections

3.2 Power Connections

3.3 Logic Inputs and Logic Outputs

3.4 Communication Connections

3.4.1 RS422 Point to Point 4 wire connection half or full duplex.The standard interface on the LDU 78.1 is RS422. The Tx+ connection from the host system is connected to +Rx (Pin 10) of the LDU 78.1. Similarly the Tx- from the host is connected to -Rx (Pin 11) , the Rx- is connected to the -Tx (Pin 12) and the Rx+ is connected to the +Tx (Pin 13). The shield connection for the RS422 cable should be connected to the power supply ground Gnd (Pin 19)

3.4.2 RS485 Multi-Drop 2 wire connection half duplex.The LDU series can be wired in a multi-drop mode where up to 32 devices can be connected to one bus. The +Rx (Pin 10) and +Tx (pin 13) should be commoned together and should be connected to the B terminal of the host RS485 interface. The -Rx (Pin 11) and the -Tx (Pin 12) should similarly be commoned and connected to the A terminal of the host RS485 interface. The ground connection (GND) from the host RS485 should be connected to the power supply ground of the LDUs. Termination resistors of 120 Ohm each should be placed across the A/B lines at host end of the bus and across the A/B lines of the last device on the bus. In addition it may be necessary to add pull up and pull down resistors (R1 & R2) to the A/B lines to prevent these lines ‘floating’ during periods of no transmission. Where the supply voltage to the RS485 line driver IC is typically 5V DC for example, the value of R1 & R2 can be 470 Ohms each. Where for example you are using a RS232 to RS485 converter with a supply voltage of 12 V DC, the value of R1 & R2 should be increased to 1K2 Ohms (1200 Ohms).

The LDU 78.1 has 2 logic inputs on pins 14 & 16 and 2 logic outputs (Open Collector) on pins 15 & 17. The common for both the logic inputs and outputs is internally connected to the ground of the power supply so no separate common supply is required. Control signals (10 - 30 V DC) applied to the logic inputs can be used to trigger a variety of weighing processes such as check-weighing, filling etc. The status of the logic inputs can be read via the LDU 78.1 communication port. The logic outputs are effectively weight dependant switches. These can be used to control alarms or filling valves etc. The load to be controlled is wired between the positive supply and the appropriate logic output terminal on the LDU 78.1.



Standard Unit with RS422 Point to Point Connections

Standard Unit with RS485 Multi-drop Connections

Top viewTx+Tx-

Rx+Rx-

Signal gnd

+12 to 24V

Gnd

Exc 67

Gnd

Gnd

Gnd

9PwrOutInOutInTxTxRxRx+

+0

1

--

0

18

Sen5Inp4Inp3Sen2Exc1

0

1617

1918

151413121110

+++---

NCNC

Power Supply Gnd

+ Power Supply

I I I

Load Cell Digitising Unit

LDU 78.1

Cert.no. DK0199 - R76 - 10.08 rev.1nmax = 10000-15°C/+55°CCE

Dmin = 0.3mV/VSI

TECHNIQUES LIMITED

www.sensortechniques.com

Signal Gnd

Power Supply Gnd

Common +Rx (Pin 10) to +Tx (Pin 13)and -Rx (Pin 11) to -Tx (Pin12)

Exc 67

Gnd

Gnd

Gnd


+0

1

--

0

18


0

1617

1918

151413121110

+++---

NCNC

Signal Gnd

Power Supply Gnd

Common +Rx (Pin 10) to +Tx (Pin 13)and -Rx (Pin 11) to -Tx (Pin12)Fit a 120 Ohm terminator to the lastdevice on the bus

MAX485

AGnd

B

RS485 Interface

120 Ohm

120 Ohm VccR1

R2

In multi-drop configuration, there can be brief periods when no transmitter is enabled, and the network is therefore allowed to float. To avoid this, pull up/pull down resistors (R1 & R2) can be added. Typical values of R1 & R2 for a 12V supply voltage will be 1K2 Ohms. For lower supply voltages such as 5V, the values of R1 & R2 can be lowered to 470 Ohms.

Fit 120 Ohm terminatorat host end

3 HARDWARE & WIRING DIAGRAMS

Bottom view

Sw1 & Sw2:Close for 4-wire load cell

Sw3: Close to enter configuration mode

Sw5: Close to connect power supply ground to chassis

Sw4: Do NOT close.Used for program download only.

Exc 67

Gnd

Gnd

Gnd


+0

1

--

0

18


0

1617

1918

151413121110

+++---

NCNC

I I I


LDU 78.1

Cert.no. DK0199 - R76 - 10.08nmax = 10000-15°C/+55°CCE

Dmin = 0.4mV/VSI

TECHNIQUES LIMITED


I I I


LDU 78.1


Dmin = 0.4mV/VSI

TECHNIQUES LIMITED


Sw

3S

w5

Sw

4Inp 32

GndNC

Sen

0

+Pwr

Out

Rx+Tx+

In0

In1

Rx-

Tx-0

Out1

1

Inp4Sen5Exc6Gnd7NC8

9

1213

1110

151417161918

++

--

--

I I I


LDU 78.1


Dmin = 0.3mV/VSI

ExcGnd

TECHNIQUES LIMITED


Sw

2S

w1 emc: MID E2



The load cell(s) are connected to pins 0 to 6 of the LDU78.1. Pins 1 & 6 provide excitation (5 V DC) to the load cell circuit, pin 1 being positive excitation (+Exc) and pin 6 negative excitation (-Exc).Pins 3 & 4 are the signal inputs to the LDU78.1 from the load cell circuit, pin 3 being the positive signal (+Sig) and pin 4 being the negative signal (-Sig).Pins 2 & 5 are the Sense connections for the LDU78.1, pin 2 being the positive sense (+Sen) and pin 5 the negative sense (-Sen). If your load cell has 6 wires ( 2 for Excitation, 2 for Signal and 2 for Sense) the sense connections provide the LDU78.1 with the voltage that reached the load cell(s) as opposed to the voltage that was sent. This enables the LDU 78.1 to correct for voltage drops on long cables.If your load cell only has 4 wires you will need to link the positive excitation (+Exc) pin (Pin 1) and the positive sense (+Sen) pin (Pin 2) and similarly the negative excitation (-Exc) pin (Pin 6) and the negative sense (-Sen) pin (Pin 5). This can be achieved simply by solder bridging pads SW1 and SW2 on the underside of the LDU 78.1 pcb. (See diagram on Page 6)Pin 0 provides a ground connection for the load cell cable screen or drain wire.

Power is provided to the LDU 78.1 via pins 18 & 19, pin 18 being the positive supply (Pwr) 12 - 24 VDC and pin 19 being the power supply ground (Gnd) 0 V.

3.1 Load Cell Connections

3.2 Power Connections

3.3 Logic Inputs and Logic Outputs

3.4 Communication Connections

3.4.1 RS422 Point to Point 4 wire connection half or full duplex.The standard interface on the LDU 78.1 is RS422. The Tx+ connection from the host system is connected to +Rx (Pin 10) of the LDU 78.1. Similarly the Tx- from the host is connected to -Rx (Pin 11) , the Rx- is connected to the -Tx (Pin 12) and the Rx+ is connected to the +Tx (Pin 13). The shield connection for the RS422 cable should be connected to the power supply ground Gnd (Pin 19)

3.4.2 RS485 Multi-Drop 2 wire connection half duplex.The LDU series can be wired in a multi-drop mode where up to 32 devices can be connected to one bus. The +Rx (Pin 10) and +Tx (pin 13) should be commoned together and should be connected to the B terminal of the host RS485 interface. The -Rx (Pin 11) and the -Tx (Pin 12) should similarly be commoned and connected to the A terminal of the host RS485 interface. The ground connection (GND) from the host RS485 should be connected to the power supply ground of the LDUs. Termination resistors of 120 Ohm each should be placed across the A/B lines at host end of the bus and across the A/B lines of the last device on the bus. In addition it may be necessary to add pull up and pull down resistors (R1 & R2) to the A/B lines to prevent these lines ‘floating’ during periods of no transmission. Where the supply voltage to the RS485 line driver IC is typically 5V DC for example, the value of R1 & R2 can be 470 Ohms each. Where for example you are using a RS232 to RS485 converter with a supply voltage of 12 V DC, the value of R1 & R2 should be increased to 1K2 Ohms (1200 Ohms).

The LDU 78.1 has 2 logic inputs on pins 14 & 16 and 2 logic outputs (Open Collector) on pins 15 & 17. The common for both the logic inputs and outputs is internally connected to the ground of the power supply so no separate common supply is required. Control signals (10 - 30 V DC) applied to the logic inputs can be used to trigger a variety of weighing processes such as check-weighing, filling etc. The status of the logic inputs can be read via the LDU 78.1 communication port. The logic outputs are effectively weight dependant switches. These can be used to control alarms or filling valves etc. The load to be controlled is wired between the positive supply and the appropriate logic output terminal on the LDU 78.1.



Standard Unit with RS422 Point to Point Connections

Standard Unit with RS485 Multi-drop Connections

Top viewTx+Tx-

Rx+Rx-

Signal gnd

+12 to 24V

Gnd

Exc 67

Gnd

Gnd

Gnd


+0

1

--

0

18


0

1617

1918

151413121110

+++---

NCNC

Power Supply Gnd

+ Power Supply

I I I


LDU 78.1


Dmin = 0.3mV/VSI

TECHNIQUES LIMITED


Signal Gnd

Power Supply Gnd

Common +Rx (Pin 10) to +Tx (Pin 13)and -Rx (Pin 11) to -Tx (Pin12)

Exc 67

Gnd

Gnd

Gnd


+0

1

--

0

18


0

1617

1918

151413121110

+++---

NCNC

Signal Gnd

Power Supply Gnd

Common +Rx (Pin 10) to +Tx (Pin 13)and -Rx (Pin 11) to -Tx (Pin12)Fit a 120 Ohm terminator to the lastdevice on the bus

MAX485

AGnd

B

RS485 Interface

120 Ohm

120 Ohm VccR1

R2

In multi-drop configuration, there can be brief periods when no transmitter is enabled, and the network is therefore allowed to float. To avoid this, pull up/pull down resistors (R1 & R2) can be added. Typical values of R1 & R2 for a 12V supply voltage will be 1K2 Ohms. For lower supply voltages such as 5V, the values of R1 & R2 can be lowered to 470 Ohms.

Fit 120 Ohm terminatorat host end

3 HARDWARE & WIRING DIAGRAMS

Bottom view

Sw1 & Sw2:Close for 4-wire load cell

Sw3: Close to enter configuration mode

Sw5: Close to connect power supply ground to chassis

Sw4: Do NOT close.Used for program download only.

Exc 67

Gnd

Gnd

Gnd


+0

1

--

0

18


0

1617

1918

151413121110

+++---

NCNC

I I I


LDU 78.1


Dmin = 0.4mV/VSI

TECHNIQUES LIMITED


I I I


LDU 78.1


Dmin = 0.4mV/VSI

TECHNIQUES LIMITED


Sw

3S

w5

Sw

4Inp 32

GndNC

Sen

0

+Pwr

Out

Rx+Tx+

In0

In1

Rx-

Tx-0

Out1

1

Inp4Sen5Exc6Gnd7NC8

9

1213

1110

151417161918

++

--

--

I I I


LDU 78.1


Dmin = 0.3mV/VSI

ExcGnd

TECHNIQUES LIMITED


Sw

2S

w1 emc: MID E2



The LDU 78.1 can also be wired in a 4 wire multi-drop mode where up to 32 devices can be connected to one bus. To achieve this simply parallel up all connections. So all Rx + terminals are connected together and are connected to the B (Tx +) terminal of the host RS485 interface. All Rx - terminals are connected together and connected to the A (Tx -) terminal of the host RS485 interface. All Tx + terminals are connected together and are connected to the B’ (Rx+) terminal of the host RS485 interface. All Tx - terminals are connected together and connected to the A’ (Rx -) terminal of the host RS485 interface. All ground connections are connected together and connected to ground connection on the host RS485. Terminating resistors (120 Ohms each) should be connected across each pair of wires both at the host end and on the last device on the bus.

3.4.3 RS485 4 Wire Multi-drop Connections Half Duplex (Recommended)

Gnd

B - Tx (Tx+)

B’- Rx (Rx+)

RS485 Interface

Vcc

A - Tx (Tx-)

A’- Rx (Rx-)

Terminators - 120 Ohm Each


R1

R2P2

P1

Span Adj. Made in EU

Zero Adj.R3R4

Made in EU F1 Buss400mAR2

P2 Span Adj.

R1P1Zero Adj.

R3R4

R1

R2P2

P1


Zero Adj.R3R4


P2 Span Adj.

R1P1Zero Adj.

R3R4

Exc 67

Gnd

Gnd

Gnd


+0

1

--

0

18


0

1617

1918

151413121110

+++---

NCNC

I I I


LDU 78.1


Dmin = 0.4mV/VSI

TECHNIQUES LIMITED


Exc 67

Gnd

Gnd

Gnd


+0

1

--

0

18


0

1617

1918

151413121110

+++---

NCNC

I I I


LDU 78.1


Dmin = 0.4mV/VSI

TECHNIQUES LIMITED




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The LDU 78.1 can also be wired in a 4 wire multi-drop mode where up to 32 devices can be connected to one bus. To achieve this simply parallel up all connections. So all Rx + terminals are connected together and are connected to the B (Tx +) terminal of the host RS485 interface. All Rx - terminals are connected together and connected to the A (Tx -) terminal of the host RS485 interface. All Tx + terminals are connected together and are connected to the B’ (Rx+) terminal of the host RS485 interface. All Tx - terminals are connected together and connected to the A’ (Rx -) terminal of the host RS485 interface. All ground connections are connected together and connected to ground connection on the host RS485. Terminating resistors (120 Ohms each) should be connected across each pair of wires both at the host end and on the last device on the bus.

3.4.3 RS485 4 Wire Multi-drop Connections Half Duplex (Recommended)

Gnd

B - Tx (Tx+)

B’- Rx (Rx+)

RS485 Interface

Vcc

A - Tx (Tx-)

A’- Rx (Rx-)



R1

R2P2

P1


Zero Adj.R3R4


P2 Span Adj.

R1P1Zero Adj.

R3R4

R1

R2P2

P1


Zero Adj.R3R4


P2 Span Adj.

R1P1Zero Adj.

R3R4

Exc 67

Gnd

Gnd

Gnd


+0

1

--

0

18


0

1617

1918

151413121110

+++---

NCNC

I I I


LDU 78.1


Dmin = 0.4mV/VSI

TECHNIQUES LIMITED


Exc 67

Gnd

Gnd

Gnd


+0

1

--

0

18


0

1617

1918

151413121110

+++---

NCNC

I I I


LDU 78.1


Dmin = 0.4mV/VSI

TECHNIQUES LIMITED




This page is intentionally left blank



4 COMMANDS OVERVIEWA

D

An

BR

CE

CG CI

CL

CM

n

CS

CZ

DP

DS

DT

DX

FD

FL

FM

GA

GG

GI

GL

GN

GS

GT

GW

Hn

HT

ID IM IN IO ISFF

GF

Netw

ork

Addre

ss

Get/S

et S

etp

oin

t n a

ctio

n

Baud R

ate

Calib

rate

Enable

- T

AC

Code

Calib

rate

Gain

(TA

C P

rote

cted)

Calib

rate

Min

imum

(TA

C P

rote

cted)

Clo

se ‘O

pen’ d

evi

ces

(Multi

-dro

p)

Calib

rate

Maxi

mum

(TA

C P

rote

cted)

Calib

rate

Save

(TA

C P

rote

cted)

Calib

rate

Zero

(TA

C P

rote

cted)

Deci

mal P

oin

t (T

AC

Pro

tect

ed)

Dis

pla

y S

tep S

ize (

TA

C P

rote

cted)

Delta

Tim

e

Duple

x

Fact

ory

Defa

ult

Filt

er

Leve

l

Filt

er

Mode

Get A

vera

ge W

eig

ht V

alu

e

Get G

ross

Weig

ht V

alu

e

Get Im

age

Get ‘L

ong’ W

eig

ht

Get N

et W

eig

ht V

alu

e

Get S

am

ple

(A

DC

valu

e)

Get Ta

re V

alu

e

Get ‘L

ong’ W

eig

ht

Get/S

et H

yste

resi

s on S

etp

oin

t n

Hold

Tim

e

Get D

evi

ce Identit

y

Read/M

odify

Contr

ol o

f O

utp

uts

Read S

tatu

s of In

puts

Read/M

odify

Outp

ut S

tatu

s

Get D

evi

ce S

tatu

s

Filt

er

Fact

or

Get F

iltere

d W

eig

ht V

alu

e

Read o

r S

et

the N

etw

ork

Addre

ss

Read o

r C

hange S

etp

oin

t A

ctio

n

Read o

r C

hange t

he B

aud R

ate

Allo

ws

acc

ess

to im

port

ant

Cal/S

et

up p

ara

mete

rs

Calib

rate

the w

eig

hin

g s

yste

m s

pan o

r gain

Read o

r m

odify

the m

inim

um

outp

ut

valu

e

Clo

ses

all

open c

om

munic

atio

n p

ath

es

(Multi

-dro

p)

Read o

r m

odify

the m

ax.

ranges

(n=

1,

2 &

3)

Save

Calib

ratio

n P

ara

mete

rs t

o E

EP

RO

M

Calib

rate

the w

eig

hin

g s

yste

m z

ero

Read o

r m

odify

the d

eci

mal p

oin

t posi

tion

Read o

r m

odify

the d

ispla

y st

ep s

ize o

r in

crem

ent

Set

the D

elta

Tim

e in

mill

iseco

nds

Sele

ct h

alf

(0)

or

full

(1)

duple

x

Rese

t to

fact

ory

defa

ult

sett

ings

Read o

r m

odify

the f

ilter

leve

l (st

rength

)

Read o

r m

odify

the f

ilter

mode

Get

the c

urr

ent

‘ave

rage’ w

eig

ht

valu

e

Get

the g

ross

weig

ht

valu

e.

Get

EE

PR

OM

Im

age a

s an I

nte

l hexf

ile

Get

curr

ent A

vera

ge,

Gro

ss a

nd S

tatu

s va

lues

Get

the n

et

weig

ht

valu

e

Get

the A

DC

sam

ple

valu

e.

Get

the t

are

valu

e

Get

the ‘L

ong’ w

eig

ht

valu

e.

Read o

r m

odify

the h

yste

resi

s va

lue o

n S

etp

oin

t n

Read/M

odify

the H

old

Tim

e

Read t

he d

evi

ce id

entit

y

Read o

r m

odify

the c

ontr

ol o

f th

e lo

gic

outp

uts

Read t

he s

tatu

s of

the lo

gic

inputs

Read o

r m

odify

the s

tatu

s of

the lo

gic

outp

uts

Get

the d

evi

ce s

tatu

s.

Defin

e t

ime o

ver

whic

h a

rolli

ng a

vera

ge is

calc

ula

ted

Get

the f

iltere

d n

et

weig

ht

valu

e

0 t

o 2

55

0 t

o 1

an

d 0

to

2

9,6

00

to

11

5,2

00

0 t

o 6

5,5

35

0 t

o 9

9,9

99

- 9

9,9

99

to

0

No

ne

0 t

o 9

9,9

99

No

ne

No

ne

0 t

o 5

1 t

o 2

00

0 t

o 6

5,5

35

0 t

o 1

No

ne

0 t

o 8

0 =

IIR

Filt

er

/ 1

= F

IR F

ilte

r

No

ne

No

ne

No

ne

No

ne

No

ne

No

ne

No

ne

No

ne

-99

,99

9 t

o 9

9,9

99

0 t

o 6

5,5

35

No

ne

00

00

to

00

11

No

ne

00

00

to

00

11

No

ne

0 t

o 1

5

No

ne

Pa

ge

39

Pa

ge

38

Pa

ge

39

Pa

ge

20

Pa

ge

22

Pa

ge

20

Pa

ge

39

Pa

ge

20

Pa

ge

23

Pa

ge

21

Pa

ge

21

Pa

ge

21

Pa

ge

19

Pa

ge

39

Pa

ge

26

Pa

ge

26

Pa

ge

31

Pa

ge

30

Pa

ge

30

Pa

ge

30

Pa

ge

30

Pa

ge

37

Pa

ge

19

Pa

ge

14

Pa

ge

35

Pa

ge

35

Pa

ge

35

Pa

ge

14

Pa

ge

22

Pa

ge

16

& 3

1

Pa

ge

30

Pa

ge

41

Pa

ge

22

Pa

ge

26

C

om

mand S

hort

Desc

riptio

n

U

sage

Pa

ram

ete

r V

alu

es

Fu

ll D

esc

rip

tion

on



4 COMMANDS OVERVIEW (Continued)

IV IZ MR

MT

NR

NT

OF

OP

PI

RS

RT

RW

RZ

SA

SD

SG

SL

Sn

SN

SP

SR

SS

ST

SW

SX

SZ

TD

TE TI

TL

TM

TN

TR

SF

Get F

irm

ware

Vers

ion N

um

ber

Move

Calib

ratio

n Z

ero

Multi

Range/m

ulti

-Inte

rval

Measu

ring T

ime

No M

otio

n R

ange

No M

otio

n T

ime

Outp

ut F

orm

at

Open C

onnect

ion

Put E

EP

RO

M im

age

Read S

erial N

um

ber

Rese

t Ta

re

Re-t

rigger

Win

dow

Rese

t S

yste

m Z

ero

Send A

vera

ge W

eig

ht

Sta

rt D

ela

y

Sta

rt a

uto

tra

nsm

ittin

g g

ross

weig

ht

Sta

rt a

uto

tra

nsm

ittin

g ‘l

ong’ w

eig

ht

Get/S

et th

e s

etp

oin

t va

lues

Sta

rt a

uto

tra

nsm

ittin

g n

et w

eig

ht

Set pre

set ta

re v

alu

e

Softw

are

rese

t

Save

Setp

oin

t P

ara

mete

rs

Set Ta

re

Sta

rt a

uto

tra

nsm

ittin

g ‘L

ong’ w

eig

ht

valu

e

Sta

rt a

uto

tra

nsm

ittin

g A

DC

sam

ple

valu

e

Set Z

ero

Tra

nsm

it D

ela

y

Trigger

Edge

Tare

Inte

rval

Trigger

Leve

l

Tare

Mode

Tare

valu

e v

olit

ile o

r non-v

olit

ile

Trigger

Sta

rt a

uto

tra

nsm

it of fil

tere

d n

et

valu

e

Get

the f

irm

ware

vers

ion n

um

ber

Re-a

dju

st c

alib

ratio

n z

ero

with

out

affect

ing g

ain

cal

Sele

ct m

ulti

range o

r m

ulti

-inte

rval

The t

ime o

ver

whic

h t

he a

vera

ge v

alu

e is

derive

d

Read o

r m

odify

the n

o-m

otio

n r

ange

Read o

r m

odify

the n

o-m

otio

n t

ime

Sele

cts

if ra

nge/d

eci

mal p

oin

t is

incl

ude in

long w

eig

ht

Open a

connect

ion t

o a

devi

ce n

um

ber

x

Put

EE

PR

OM

image a

s a I

nte

l hexf

ile

Read t

he s

erial n

um

ber

of

the d

evi

ce

Cance

ls t

are

valu

e -

unit

reve

rts

to G

ross

weig

hin

g

Read/m

odify

the r

e-t

rigger

win

dow

Rest

ore

s th

e c

alib

ratio

n z

ero

poin

t

Sta

rt a

uto

tra

nsm

ittin

g t

he A

vera

ge W

eig

ht

Read o

r se

t th

e d

ela

y betw

een t

rigger

& m

easu

rem

en

t

Sta

rt a

uto

tra

nsm

ittin

g t

he g

ross

weig

ht

valu

e

Sta

rt a

uto

tra

nsm

ittin

g t

he ‘l

ong’ w

eig

ht

valu

e

Read o

r m

odify

the s

etp

oin

t va

lues

Sta

rt a

uto

tra

nsm

ittin

g t

he n

et

weig

ht

valu

e

Set

a p

rese

t ta

re v

alu

e

Cause

s th

e L

DU

to p

erf

orm

a s

oft

ware

rese

t

Save

Setp

oin

t para

mete

rs t

o E

EP

RO

M

Sets

a t

are

valu

e a

nd p

uts

the L

DU

in n

et

mode

Sta

rt a

uto

tra

nsm

ittin

g t

he ‘l

ong’ w

eig

ht

valu

es

Sta

rt a

uto

tra

nsm

ittin

g t

he A

DC

sam

ple

valu

es

Set

a n

ew

sys

tem

zero

Set

dela

y betw

een r

ece

ivin

g c

om

mand &

resp

ondin

g

Sele

cts

trig

ger

on a

falli

ng (

0)

or

risi

ng e

dge (

1)

Read o

r se

t th

e T

are

Inte

rval (

Dyn

am

ic T

are

)

Set

trig

ger

leve

l at

whic

h m

easu

rem

ent

cycl

e s

tart

s

Set Ta

re M

ode t

o R

76 c

om

patib

le (

defa

ult

1)

Set

tare

mode t

o v

olit

ile (

defa

ult

0)

or

non-v

olit

ile (

1)

Soft

ware

trigger

to s

tart

measu

rem

ent

cycl

e.

Sta

rt a

uto

tra

nsm

ittin

g t

he f

iltere

d n

et

weig

ht

valu

e

No

ne

No

ne

0 t

o 1

0 t

o 5

00

ms

0 t

o 6

5,5

35

0 t

o 6

5,5

35

0 t

o 3

0 t

o 2

55

Inte

l He

xfile

No

ne

No

ne

0 t

o 6

5,

53

5

No

ne

No

ne

No

ne

No

ne

No

ne

0 t

o 9

9,9

99

No

ne

No

ne

No

ne

No

ne

No

ne

No

ne

0 t

o 2

55

0 t

o 1

0 t

o 6

5,5

35

0 t

o 9

9,9

99

0 t

o 1

0 t

o 1

No

ne

0 t

o 5

00

ms

-99

,99

9 t

o 9

9,9

99

No

ne

Pa

ge

14

Pa

ge

22

Pa

ge

21

Pa

ge

16

Pa

ge

25

Pa

ge

25

Pa

ge

31

Pa

ge

40

Pa

ge

41

Pa

ge

15

Pa

ge

29

Pa

ge

19

Pa

ge

28

Pa

ge

33

Pa

ge

33

Pa

ge

34

Pa

ge

33

Pa

ge

29

Pa

ge

15

Pa

ge

41

Pa

ge

28

Pa

ge

33

Pa

ge

34

Pa

ge

28

Pa

ge

40

Pa

ge

17

Pa

ge

18

Pa

ge

17

Pa

ge

24

Pa

ge

24

Pa

ge

17

Pa

ge

16

Pa

ge

37

Pa

ge

?

C

om

mand S

hort

Desc

riptio

n

U

sage

P

ara

me

ter

Va

lue

s

F

ull

De

scrip

tion

on



4 COMMANDS OVERVIEW

AD

An

BR

CE

CG CI

CL

CM

n

CS

CZ

DP

DS

DT

DX

FD

FL

FM

GA

GG

GI

GL

GN

GS

GT

GW

Hn

HT

ID IM IN IO ISFF

GF

Netw

ork

Addre

ss

Get/S

et S

etp

oin

t n a

ctio

n

Baud R

ate

Calib

rate

Enable

- T

AC

Code

Calib

rate

Gain

(TA

C P

rote

cted)

Calib

rate

Min

imum

(TA

C P

rote

cted)

Clo

se ‘O

pen’ d

evi

ces

(Multi

-dro

p)

Calib

rate

Maxi

mum

(TA

C P

rote

cted)

Calib

rate

Save

(TA

C P

rote

cted)

Calib

rate

Zero

(TA

C P

rote

cted)

Deci

mal P

oin

t (T

AC

Pro

tect

ed)

Dis

pla

y S

tep S

ize (

TA

C P

rote

cted)

Delta

Tim

e

Duple

x

Fact

ory

Defa

ult

Filt

er

Leve

l

Filt

er

Mode

Get A

vera

ge W

eig

ht V

alu

e

Get G

ross

Weig

ht V

alu

e

Get Im

age

Get ‘L

ong’ W

eig

ht

Get N

et W

eig

ht V

alu

e

Get S

am

ple

(A

DC

valu

e)

Get Ta

re V

alu

e

Get ‘L

ong’ W

eig

ht

Get/S

et H

yste

resi

s on S

etp

oin

t n

Hold

Tim

e

Get D

evi

ce Identit

y

Read/M

odify

Contr

ol o

f O

utp

uts

Read S

tatu

s of In

puts

Read/M

odify

Outp

ut S

tatu

s

Get D

evi

ce S

tatu

s

Filt

er

Fact

or

Get F

iltere

d W

eig

ht V

alu

e

Read o

r S

et

the N

etw

ork

Addre

ss

Read o

r C

hange S

etp

oin

t A

ctio

n

Read o

r C

hange t

he B

aud R

ate

Allo

ws

acc

ess

to im

port

ant

Cal/S

et

up p

ara

mete

rs

Calib

rate

the w

eig

hin

g s

yste

m s

pan o

r gain

Read o

r m

odify

the m

inim

um

outp

ut

valu

e

Clo

ses

all

open c

om

munic

atio

n p

ath

es

(Multi

-dro

p)

Read o

r m

odify

the m

ax.

ranges

(n=

1,

2 &

3)

Save

Calib

ratio

n P

ara

mete

rs t

o E

EP

RO

M

Calib

rate

the w

eig

hin

g s

yste

m z

ero

Read o

r m

odify

the d

eci

mal p

oin

t posi

tion

Read o

r m

odify

the d

ispla

y st

ep s

ize o

r in

crem

ent

Set

the D

elta

Tim

e in

mill

iseco

nds

Sele

ct h

alf

(0)

or

full

(1)

duple

x

Rese

t to

fact

ory

defa

ult

sett

ings

Read o

r m

odify

the f

ilter

leve

l (st

rength

)

Read o

r m

odify

the f

ilter

mode

Get

the c

urr

ent

‘ave

rage’ w

eig

ht

valu

e

Get

the g

ross

weig

ht

valu

e.

Get

EE

PR

OM

Im

age a

s an I

nte

l hexf

ile

Get

curr

ent A

vera

ge,

Gro

ss a

nd S

tatu

s va

lues

Get

the n

et

weig

ht

valu

e

Get

the A

DC

sam

ple

valu

e.

Get

the t

are

valu

e

Get

the ‘L

ong’ w

eig

ht

valu

e.

Read o

r m

odify

the h

yste

resi

s va

lue o

n S

etp

oin

t n

Read/M

odify

the H

old

Tim

e

Read t

he d

evi

ce id

entit

y

Read o

r m

odify

the c

ontr

ol o

f th

e lo

gic

outp

uts

Read t

he s

tatu

s of

the lo

gic

inputs

Read o

r m

odify

the s

tatu

s of

the lo

gic

outp

uts

Get

the d

evi

ce s

tatu

s.

Defin

e t

ime o

ver

whic

h a

rolli

ng a

vera

ge is

calc

ula

ted

Get

the f

iltere

d n

et

weig

ht

valu

e

0 t

o 2

55

0 t

o 1

an

d 0

to

2

9,6

00

to

11

5,2

00

0 t

o 6

5,5

35

0 t

o 9

9,9

99

- 9

9,9

99

to

0

No

ne

0 t

o 9

9,9

99

No

ne

No

ne

0 t

o 5

1 t

o 2

00

0 t

o 6

5,5

35

0 t

o 1

No

ne

0 t

o 8

0 =

IIR

Filt

er

/ 1

= F

IR F

ilte

r

No

ne

No

ne

No

ne

No

ne

No

ne

No

ne

No

ne

No

ne

-99

,99

9 t

o 9

9,9

99

0 t

o 6

5,5

35

No

ne

00

00

to

00

11

No

ne

00

00

to

00

11

No

ne

0 t

o 1

5

No

ne

Pa

ge

39

Pa

ge

38

Pa

ge

39

Pa

ge

20

Pa

ge

22

Pa

ge

20

Pa

ge

39

Pa

ge

20

Pa

ge

23

Pa

ge

21

Pa

ge

21

Pa

ge

21

Pa

ge

19

Pa

ge

39

Pa

ge

26

Pa

ge

26

Pa

ge

31

Pa

ge

30

Pa

ge

30

Pa

ge

30

Pa

ge

30

Pa

ge

37

Pa

ge

19

Pa

ge

14

Pa

ge

35

Pa

ge

35

Pa

ge

35

Pa

ge

14

Pa

ge

22

Pa

ge

16

& 3

1

Pa

ge

30

Pa

ge

41

Pa

ge

22

Pa

ge

26

C

om

mand S

hort

Desc

riptio

n

U

sage

Pa

ram

ete

r V

alu

es

Fu

ll D

esc

rip

tion

on



4 COMMANDS OVERVIEW (Continued)IV IZ MR

MT

NR

NT

OF

OP

PI

RS

RT

RW

RZ

SA

SD

SG

SL

Sn

SN

SP

SR

SS

ST

SW

SX

SZ

TD

TE TI

TL

TM

TN

TR

SF

Get F

irm

ware

Vers

ion N

um

ber

Move

Calib

ratio

n Z

ero

Multi

Range/m

ulti

-Inte

rval

Measu

ring T

ime

No M

otio

n R

ange

No M

otio

n T

ime

Outp

ut F

orm

at

Open C

onnect

ion

Put E

EP

RO

M im

age

Read S

erial N

um

ber

Rese

t Ta

re

Re-t

rigger

Win

dow

Rese

t S

yste

m Z

ero

Send A

vera

ge W

eig

ht

Sta

rt D

ela

y

Sta

rt a

uto

tra

nsm

ittin

g g

ross

weig

ht

Sta

rt a

uto

tra

nsm

ittin

g ‘l

ong’ w

eig

ht

Get/S

et th

e s

etp

oin

t va

lues

Sta

rt a

uto

tra

nsm

ittin

g n

et w

eig

ht

Set pre

set ta

re v

alu

e

Softw

are

rese

t

Save

Setp

oin

t P

ara

mete

rs

Set Ta

re

Sta

rt a

uto

tra

nsm

ittin

g ‘L

ong’ w

eig

ht

valu

e

Sta

rt a

uto

tra

nsm

ittin

g A

DC

sam

ple

valu

e

Set Z

ero

Tra

nsm

it D

ela

y

Trigger

Edge

Tare

Inte

rval

Trigger

Leve

l

Tare

Mode

Tare

valu

e v

olit

ile o

r non-v

olit

ile

Trigger

Sta

rt a

uto

tra

nsm

it of fil

tere

d n

et

valu

e

Get

the f

irm

ware

vers

ion n

um

ber

Re-a

dju

st c

alib

ratio

n z

ero

with

out

affect

ing g

ain

cal

Sele

ct m

ulti

range o

r m

ulti

-inte

rval

The t

ime o

ver

whic

h t

he a

vera

ge v

alu

e is

derive

d

Read o

r m

odify

the n

o-m

otio

n r

ange

Read o

r m

odify

the n

o-m

otio

n t

ime

Sele

cts

if ra

nge/d

eci

mal p

oin

t is

incl

ude in

long w

eig

ht

Open a

connect

ion t

o a

devi

ce n

um

ber

x

Put

EE

PR

OM

image a

s a I

nte

l hexf

ile

Read t

he s

erial n

um

ber

of

the d

evi

ce

Cance

ls t

are

valu

e -

unit

reve

rts

to G

ross

weig

hin

g

Read/m

odify

the r

e-t

rigger

win

dow

Rest

ore

s th

e c

alib

ratio

n z

ero

poin

t

Sta

rt a

uto

tra

nsm

ittin

g t

he A

vera

ge W

eig

ht

Read o

r se

t th

e d

ela

y betw

een t

rigger

& m

easu

rem

en

t

Sta

rt a

uto

tra

nsm

ittin

g t

he g

ross

weig

ht

valu

e

Sta

rt a

uto

tra

nsm

ittin

g t

he ‘l

ong’ w

eig

ht

valu

e

Read o

r m

odify

the s

etp

oin

t va

lues

Sta

rt a

uto

tra

nsm

ittin

g t

he n

et

weig

ht

valu

e

Set

a p

rese

t ta

re v

alu

e

Cause

s th

e L

DU

to p

erf

orm

a s

oft

ware

rese

t

Save

Setp

oin

t para

mete

rs t

o E

EP

RO

M

Sets

a t

are

valu

e a

nd p

uts

the L

DU

in n

et

mode

Sta

rt a

uto

tra

nsm

ittin

g t

he ‘l

ong’ w

eig

ht

valu

es

Sta

rt a

uto

tra

nsm

ittin

g t

he A

DC

sam

ple

valu

es

Set

a n

ew

sys

tem

zero

Set

dela

y betw

een r

ece

ivin

g c

om

mand &

resp

ondin

g

Sele

cts

trig

ger

on a

falli

ng (

0)

or

risi

ng e

dge (

1)

Read o

r se

t th

e T

are

Inte

rval (

Dyn

am

ic T

are

)

Set

trig

ger

leve

l at

whic

h m

easu

rem

ent

cycl

e s

tart

s

Set Ta

re M

ode t

o R

76 c

om

patib

le (

defa

ult

1)

Set

tare

mode t

o v

olit

ile (

defa

ult

0)

or

non-v

olit

ile (

1)

Soft

ware

trigger

to s

tart

measu

rem

ent

cycl

e.

Sta

rt a

uto

tra

nsm

ittin

g t

he f

iltere

d n

et

weig

ht

valu

e

No

ne

No

ne

0 t

o 1

0 t

o 5

00

ms

0 t

o 6

5,5

35

0 t

o 6

5,5

35

0 t

o 3

0 t

o 2

55

Inte

l He

xfile

No

ne

No

ne

0 t

o 6

5,

53

5

No

ne

No

ne

No

ne

No

ne

No

ne

0 t

o 9

9,9

99

No

ne

No

ne

No

ne

No

ne

No

ne

No

ne

0 t

o 2

55

0 t

o 1

0 t

o 6

5,5

35

0 t

o 9

9,9

99

0 t

o 1

0 t

o 1

No

ne

0 t

o 5

00

ms

-99

,99

9 t

o 9

9,9

99

No

ne

Pa

ge

14

Pa

ge

22

Pa

ge

21

Pa

ge

16

Pa

ge

25

Pa

ge

25

Pa

ge

31

Pa

ge

40

Pa

ge

41

Pa

ge

15

Pa

ge

29

Pa

ge

19

Pa

ge

28

Pa

ge

33

Pa

ge

33

Pa

ge

34

Pa

ge

33

Pa

ge

29

Pa

ge

15

Pa

ge

41

Pa

ge

28

Pa

ge

33

Pa

ge

34

Pa

ge

28

Pa

ge

40

Pa

ge

17

Pa

ge

18

Pa

ge

17

Pa

ge

24

Pa

ge

24

Pa

ge

17

Pa

ge

16

Pa

ge

37

Pa

ge

?

C

om

mand S

hort

Desc

riptio

n

U

sage

P

ara

me

ter

Va

lue

s

F

ull

De

scrip

tion

on




TS

TT

TW

UR

WP

ZA ZI

ZR

ZT

WT

Re-t

rigger

stop

Re-t

rigger

time

Tare

Win

dow

Read o

r m

odify

the u

pdate

rate

Save

setu

p p

ara

mete

rs

Set sy

stem

zero

- a

vera

ge

Initi

al Z

ero

(TA

C p

rote

cted)

Zero

Range (

TA

C P

rote

cted)

Zero

tra

ck (

TA

C p

rote

cted)

Read o

r m

odify

the w

arm

up d

ela

y tim

e

Read/m

odify

the r

e-t

rigger

stop le

vel

Read/m

odify

the r

e-t

rigger

time

Read o

r se

t th

e T

are

Win

dow

(D

ynam

ic T

are

)

Read o

r m

odify

the u

pdate

rate

Save

setu

p p

ara

mete

rs t

o E

EP

RO

M

Set

syst

em

zero

usi

ng t

he T

are

Inte

rval T

I

Set

the in

itial z

ero

range

Set

the z

ero

range

Zero

tra

ck o

ff (

0)

or

Zero

tra

ck o

n (

1 .

..255)

Read o

r m

odify

the w

arm

up d

ela

y tim

e

0 t

o 6

5,5

35

0 t

o 6

5,5

35

0 t

o 6

5,5

35

0 t

o 7

No

ne

0 t

o 6

5,5

35

No

ne

0 t

o 9

9,9

99

0 t

o 9

9,9

99

0 t

o 2

55

Pa

ge

19

Pa

ge

19

Pa

ge

18

Pa

ge

27

Pa

ge

41

Pa

ge

23

Pa

ge

29

Pa

ge

23

Pa

ge

23

Pa

ge

22

C

om

mand

S

hort

Desc

riptio

n

Usa

ge

Pa

ram

ete

r V

alu

es

Fu

ll D

esc

rip

tion

on

Ple

ase

note

tha

t co

mm

ands

whic

h a

re g

reye

d o

ut are

not ava

ilable

on this

model

5 COMMANDS



For better clarity, all commands are divided into groups as described on the following pages.

5.1 System diagnostic Commands - ID, IV, IS, SR, RS 14

5.2 Check Weigher Commands - SD, MT, GA, TE, TR, TL, TW, TI, RW, TT, HT, DT, TS 16

5.3 Calibration Commands - CE, CM n, CI, MR, DS, DP, CZ, CG, ZT, FD, IZ, ZR, ZI, WT, CS, TM, TN 20

5.4 Motion detection Commands - NR, NT 25

5.5 Filter setting Commands - FM, FL, UR 26

5.6 Set Zero/Tare and Reset Zero/Tare Commands - SZ, RZ, ST, RT, ZA, SP 28

5.7 Output Commands - GG, GN, GT, GS, GW, GA, GL, OF 30

5.8 Auto-transmit Commands - SG, SN, SA, SW, SL, SX 33

5.9 Commands for external I/O control - IN, IO, IM 35

5.10 Setpoint Commands - Sn, Hn, An 37

5.11 Communication setup Commands - AD, CL, BR, DX, OP, TD 39

5.12 Save calibration, setup & setpoint parameters Commands - CS, WP, SS, PI, GI 41

Leftmost 3-digit value: Rightmost 3-digit value:

1 Signal stable 1 (not used)

2 Zero action performed 2 (not used)

4 Tare active 4 (not used)

8 Centre of zero (± 0.25d) 8 (not used)

16 Input 0 active 16 (not used)


64 Output 0 active 64 (not used)


Master (PC / PLC) sends

IS S:067000 (example)

LDU XX.X responds


IV V:0201

LDU XX.X responds


ID D:7813

LDU XX.X responds



Use these commands to get the LDU XX.X type, firmware version or device status. These commands are sent without parameters.

IS Request device status

The response to this request comprises of two 3-digit decimal values, which can be decoded according to the table below:

For example the result S:067000 decodes as follows:

Signal Stable (no-motion) 1Zero action 2Output 0 active 64

Total 67

Please note that the bits that are not used are set to zero.

The response to this request gives the firmware version of the active device.

IV Request of firmware version

ID Request of device identity

The response to this request gives the actual identity of the active device. This is particularly useful when trying to identify different device types on a bus.

5.1 System diagnosis Commands – ID, IV, IS, SR, RS



SR Software Reset

This command will respond with ‘OK’ and after a maximum of 400 ms perform a complete reset of the LDU. This has the same functionality as powering off and on again (hardware reset).


SR OK

LDU XX.X responds

RS Read Device Serial Number

Issuing the RS command without any parameters will return the current serial number. Devices which have not been programmed with a serial number will show serial number 0 or -1 when using new firmware.

Master (PC / PLC) sends LDU XX.X responds Result

RS S:12345678 Current Serial Number is 12345678

Leftmost 3-digit value: Rightmost 3-digit value:

1 Signal stable 1 (not used)

2 Zero action performed 2 (not used)

4 Tare active 4 (not used)

8 Centre of zero (± 0.25d) 8 (not used)






IS S:067000 (example)

LDU XX.X responds


IV V:0201

LDU XX.X responds


ID D:7813

LDU XX.X responds



Use these commands to get the LDU XX.X type, firmware version or device status. These commands are sent without parameters.

IS Request device status

The response to this request comprises of two 3-digit decimal values, which can be decoded according to the table below:

For example the result S:067000 decodes as follows:

Signal Stable (no-motion) 1Zero action 2Output 0 active 64

Total 67

Please note that the bits that are not used are set to zero.

The response to this request gives the firmware version of the active device.

IV Request of firmware version

ID Request of device identity

The response to this request gives the actual identity of the active device. This is particularly useful when trying to identify different device types on a bus.

5.1 System diagnosis Commands – ID, IV, IS, SR, RS



SR Software Reset

This command will respond with ‘OK’ and after a maximum of 400 ms perform a complete reset of the LDU. This has the same functionality as powering off and on again (hardware reset).


SR OK

LDU XX.X responds

RS Read Device Serial Number

Issuing the RS command without any parameters will return the current serial number. Devices which have not been programmed with a serial number will show serial number 0 or -1 when using new firmware.


RS S:12345678 Current Serial Number is 12345678



5.2 Check Weigher Commands SD, MT, GA, TE, TR, TL, TW, TI, RW, TT, HT, DT, TS

Note: All setups should be stored with the WP command before power off.

Set the delay (in milliseconds) between the falling or rising edge of the trigger pulse and the start of the measurement cycle. Permitted values are 0 ... 500 ms. Factory default setting SD = 0 [Start Delay = 0 ms]. To check the current setting issue the command without any additional parameters. To change the setting issue the command with the additional parameter. See table below.

SD Start Delay 0 ... 500 milliseconds

Set the time (in milliseconds) during which the weight average will be calculated. Permitted values are 0 ... 500 milliseconds. To check the current setting issue the command without any additional parameters. To change the setting issue the command with the additional parameter. See table below.

MT Measuring Time. Range 0 ... 500 milliseconds

Please note that if MT = 0 then the trigger and average functions are disabled. The factory default setting MT=0 [Measuring Time = 0]. See check weighing timing diagram on page 18


MT

MT_200

M+00100

OK

Measuring Time set to 100 milliseconds

Measuring Time changed to 200 msecs

See check weighing timing diagram on page 18


SD

SD_200

S+00100

OK

Start Delay set to 100 milliseconds

Start Delay changed to 200 milliseconds

See check weighing timing diagram on page 18. Also see the SA command under the Auto Transmit command section on page 31.

Please note that during the period after the measuring cycle has been triggered but before the value of GA has been updated, the GA command will return a value 99999

Issuing the GA command, the LDU returns the current weight average calculated over the Measuring Time MT. The GA value is only updated after another measuring cycle is completed. the format of the response includes any decimal places etc. which may have been set.

GA Get Average


GA A+01.100 Weight average (over time MT) GA = 1.100g




This command sets the trigger level above or below which (depending if the Trigger Edge TE is set to a rising or falling edge) the measuring cycle starts. Permitted values 0 ... 99999. Factory default setting TL = 99999. To check the current setting issue the command without any additional parameters. To change the setting issue the command with the additional parameter. See table below.

TL Trigger Level


TL

TL_1000

T+99999

OK

Trigger Level set to 99,999 divisions

Trigger Level changed to 1,000 divisions

See check weighing timing diagram on page 18.

Please note that an electrical input (10 - 30V relative to the power supply 0V) on Logic Input 1 will act as a hardware trigger starting the measuring cycle See Section 3.3 on page 7. The TE command also applies to this electrical input. So you can use a photo cell connected to Logic Input 1 and trigger the timing cycle off ‘a falling edge’ TE = 0 (trailing edge of the pack)

This command will start the measuring cycle immediately in the same way as the hardware trigger. The average value (see GA below) will be calculated over the Measuring Time (MT) after a Start Delay (SD). The GA value is only updated after a new measuring cycle has been completed.

TR Trigger


TR OK Measuring cycle triggered

Using the TE command you can select whether the measuring cycle is triggered on a rising or falling edge. Permitted values are 0 [Falling Edge] or 1 [Rising Edge]. Factory default setting TE = 0 [Falling Edge]. To check the current setting issue the command without any additional parameters. To change the setting issue the command with the additional parameter. See table below.

TE Trigger Edge



TE

TE_0

E:001

OK

Trigger Edge set on a rising edge

Trigger Edge changed to a falling edge



5.2 Check Weigher Commands SD, MT, GA, TE, TR, TL, TW, TI, RW, TT, HT, DT, TS

Note: All setups should be stored with the WP command before power off.

Set the delay (in milliseconds) between the falling or rising edge of the trigger pulse and the start of the measurement cycle. Permitted values are 0 ... 500 ms. Factory default setting SD = 0 [Start Delay = 0 ms]. To check the current setting issue the command without any additional parameters. To change the setting issue the command with the additional parameter. See table below.

SD Start Delay 0 ... 500 milliseconds

Set the time (in milliseconds) during which the weight average will be calculated. Permitted values are 0 ... 500 milliseconds. To check the current setting issue the command without any additional parameters. To change the setting issue the command with the additional parameter. See table below.

MT Measuring Time. Range 0 ... 500 milliseconds

Please note that if MT = 0 then the trigger and average functions are disabled. The factory default setting MT=0 [Measuring Time = 0]. See check weighing timing diagram on page 18


MT

MT_200

M+00100

OK

Measuring Time set to 100 milliseconds

Measuring Time changed to 200 msecs



SD

SD_200

S+00100

OK

Start Delay set to 100 milliseconds

Start Delay changed to 200 milliseconds

See check weighing timing diagram on page 18. Also see the SA command under the Auto Transmit command section on page 31.

Please note that during the period after the measuring cycle has been triggered but before the value of GA has been updated, the GA command will return a value 99999


GA Get Average






This command sets the trigger level above or below which (depending if the Trigger Edge TE is set to a rising or falling edge) the measuring cycle starts. Permitted values 0 ... 99999. Factory default setting TL = 99999. To check the current setting issue the command without any additional parameters. To change the setting issue the command with the additional parameter. See table below.

TL Trigger Level


TL

TL_1000

T+99999

OK

Trigger Level set to 99,999 divisions

Trigger Level changed to 1,000 divisions

See check weighing timing diagram on page 18.

Please note that an electrical input (10 - 30V relative to the power supply 0V) on Logic Input 1 will act as a hardware trigger starting the measuring cycle See Section 3.3 on page 7. The TE command also applies to this electrical input. So you can use a photo cell connected to Logic Input 1 and trigger the timing cycle off ‘a falling edge’ TE = 0 (trailing edge of the pack)

This command will start the measuring cycle immediately in the same way as the hardware trigger. The average value (see GA below) will be calculated over the Measuring Time (MT) after a Start Delay (SD). The GA value is only updated after a new measuring cycle has been completed.

TR Trigger


TR OK Measuring cycle triggered

Using the TE command you can select whether the measuring cycle is triggered on a rising or falling edge. Permitted values are 0 [Falling Edge] or 1 [Rising Edge]. Factory default setting TE = 0 [Falling Edge]. To check the current setting issue the command without any additional parameters. To change the setting issue the command with the additional parameter. See table below.

TE Trigger Edge



TE

TE_0

E:001

OK

Trigger Edge set on a rising edge

Trigger Edge changed to a falling edge

Weight (g)

Time (ms)

trigger point

Timing Control Diagram

MTSD(Measuring Time)(Start Delay)

TL(Trigger Level)

TW(Tare Widow )

TI(Tare Interval )

TE(Trigger Edge)

The Dynamic Tare feature allows a new tare value to be calculated over a time interval (TI) when the weight value is within a certain band or window (TW). If the weight value goes outside the Tare Window before the Tare Interval is complete, the newly calculated tare will be discarded and the previous tare value will be used. This is useful in checkweigher applications when you want to set a new tare value automatically during a “quiet period” when there is no product going down the belt.

Dynamic Tare

Use this command to set or check the Tare Window value. To check the TW value issue the TW command without any parameters. To set a new TW value, issue the TW command followed by the required Tare Window value. Permitted values between 0 and 65535. Factory Default 0.

TW Tare Window (Dynamic Tare)


TW

TW_200

W+00100

OK

Tare Window set to 100 display divisions

Tare Window changed to 200 display divs.

TI Tare Interval (Dynamic Tare)

Use this command to set or check the Tare Interval value. To check the TI value issue the TI command without any parameters. To set a new TI value, issue the TI command followed by the required Tare Interval value. Permitted values between 0 and 65535. Factory Default 0.


TI

TW_200

W+00100

OK

Tare Window set to 100 milliseconds

Tare Window changed to 200 milliseconds.

Average Weight


LDU78.1 Manual Issue 1g Page 19 LDU78.1 Manual Issue 1g



RW

RW_1000

R+65535

OK

This command sets the re-trigger time in milliseconds [0 - 65535]. Re-trigger time is the average time used by the re-trigger function. If set to 0 the re-trigger function is disabled. Factory default 0

TT Re-Trigger Time


TT

TT_100

T+00000

OK

Re-trigger time set to 0 milliseconds

Re-trigger time changed to 100 milliseconds

This command sets the re-trigger window in counts (digits) without decimal point (0 - 65535). If the weight value relative to the current average value changes by more than the RW value, the average cycle will be restarted using the value of TT as the measuring time. To automatically issue the re-trigger command, the time period over which an increase of weight average is measured has to be defined by using the command DT. Factory default setting 65535

RW Re-Trigger Window


HT

HT_100

H+00000

OK

Hold time set to 0 milliseconds

Hold time changed to 100 milliseconds

This command sets the hold time in milliseconds [0 - 65535]. If during the hold time, the weight value exceeds the setpoint, the digital output will not switch. This can be useful to prevent digital outputs switching when the weight value temporarily exceeds the setpoint due to the kinetic energy of the product falling into the container etc. Factory default 0

HT Hold Time

This command sets the delta time in milliseconds [0 - 65535]. During MT and TT time frames ‘sub averages’ will be calculated by the system over the time DT. If a sub average is outside the re-trigger window, the re-trigger function is automatically started. Factory default 50

DT Delta Time


TS

TS_100

T+65535

OK

Re-trigger stop level set to 65535 counts

Re-trigger stop level changed to 100 counts

This command sets the re-trigger stop level in counts without decimal point [0 - 65535]. When there is a (TS) decrease in weight, relative to the current average value, the re-trigger function is stopped. Factory default 65535

TS Re-Trigger Stop Level

The re-trigger level is set at 65,535 counts

Re-trigger level changed to 1000 counts


DT

DT_100

T+00050

OK

Delta time set to 50 milliseconds

Delta time changed to 100 milliseconds

Weight (g)

Time (ms)

trigger point

Timing Control Diagram

MTSD(Measuring Time)(Start Delay)

TL(Trigger Level)

TW(Tare Widow )

TI(Tare Interval )

TE(Trigger Edge)

The Dynamic Tare feature allows a new tare value to be calculated over a time interval (TI) when the weight value is within a certain band or window (TW). If the weight value goes outside the Tare Window before the Tare Interval is complete, the newly calculated tare will be discarded and the previous tare value will be used. This is useful in checkweigher applications when you want to set a new tare value automatically during a “quiet period” when there is no product going down the belt.

Dynamic Tare

Use this command to set or check the Tare Window value. To check the TW value issue the TW command without any parameters. To set a new TW value, issue the TW command followed by the required Tare Window value. Permitted values between 0 and 65535. Factory Default 0.

TW Tare Window (Dynamic Tare)


TW

TW_200

W+00100

OK

Tare Window set to 100 display divisions

Tare Window changed to 200 display divs.

TI Tare Interval (Dynamic Tare)

Use this command to set or check the Tare Interval value. To check the TI value issue the TI command without any parameters. To set a new TI value, issue the TI command followed by the required Tare Interval value. Permitted values between 0 and 65535. Factory Default 0.


TI

TW_200

W+00100

OK

Tare Window set to 100 milliseconds

Tare Window changed to 200 milliseconds.

Average Weight


Page 18 LDU78.1 Manual Issue 1g LDU78.1 Manual Issue 1g



RW

RW_1000

R+65535

OK

This command sets the re-trigger time in milliseconds [0 - 65535]. Re-trigger time is the average time used by the re-trigger function. If set to 0 the re-trigger function is disabled. Factory default 0

TT Re-Trigger Time


TT

TT_100

T+00000

OK

Re-trigger time set to 0 milliseconds

Re-trigger time changed to 100 milliseconds

This command sets the re-trigger window in counts (digits) without decimal point (0 - 65535). If the weight value relative to the current average value changes by more than the RW value, the average cycle will be restarted using the value of TT as the measuring time. To automatically issue the re-trigger command, the time period over which an increase of weight average is measured has to be defined by using the command DT. Factory default setting 65535

RW Re-Trigger Window


HT

HT_100

H+00000

OK

Hold time set to 0 milliseconds

Hold time changed to 100 milliseconds

This command sets the hold time in milliseconds [0 - 65535]. If during the hold time, the weight value exceeds the setpoint, the digital output will not switch. This can be useful to prevent digital outputs switching when the weight value temporarily exceeds the setpoint due to the kinetic energy of the product falling into the container etc. Factory default 0

HT Hold Time

This command sets the delta time in milliseconds [0 - 65535]. During MT and TT time frames ‘sub averages’ will be calculated by the system over the time DT. If a sub average is outside the re-trigger window, the re-trigger function is automatically started. Factory default 50

DT Delta Time


TS

TS_100

T+65535

OK

Re-trigger stop level set to 65535 counts

Re-trigger stop level changed to 100 counts

This command sets the re-trigger stop level in counts without decimal point [0 - 65535]. When there is a (TS) decrease in weight, relative to the current average value, the re-trigger function is stopped. Factory default 65535

TS Re-Trigger Stop Level

The re-trigger level is set at 65,535 counts

Re-trigger level changed to 1000 counts


DT

DT_100

T+00050

OK

Delta time set to 50 milliseconds

Delta time changed to 100 milliseconds



Note: TAC represents the Traceable Access Code (calibration counter) which increments every time new calibration data is stored. Calibration values are only stored in EEPROM when the CS command is issued (see CS command on Page 23)

With this command you can either read the current TAC value or enable a calibration command.check the current TAC value issue the command without any additional parameters. To enable a calibration command, issue the CE command with the current TAC value. See table below.

To

This command MUST be issued PRIOR to any attempt to change calibration parameters such as CZ, CG etc. In legal for trade applications the TAC value can be used to check if any critical parameters have been changed without re-verification. After each calibration the TAC counter increases by 1.

CE TAC counter reading


CE

CE_17

E+00017 (example)

OK

Current TAC value is 17

Calibration commands enabled

5.2 Calibration Commands CE, CM n, CI, MR, DS, DP, CZ, CG, ZT, FD, IZ, ZR, ZI, WT, CS, TM, TN

This command sets the maximum output value in interval or range n (1<=n<=3).of CM n are between 1 and 999,999.. To check the current value issue the CM n command without any additional parameters. To change the value of CM n, issue the CE command with the current TAC value and then CM n and the new setting. See table below.

Permitted values

The value of CM n will determine the point at which the output will change to “oooooo” signifying over-range. Factory default value CM 1 = 999999, CM 2 = 0, CM 3 = 0

CM n Set maximum output value

This command sets the minimum output value.Factory default value CI = -9 for approved applications. To check the current value issue the CI command without any additional parameters. To change the value of CI, issue the CE command with the current TAC value and then CI and the new setting. See table below.

Permitted values are between 0 and -999,999.

CI Set minimum output value


CE

CI

CI_-10000

CE_17

E+00017 (example)

I-000009

OK

OK


Current output minimum is set to -9

Output minimum changed to -10,000


The value of CM will determine the point at which the output will change to “uuuuuuu” signifying under-range.


CE

CM_1

CM_1_50000

CE_17

E+00017 (example)

M+30000

OK

OK


Current output maximum is set to 30,000

Output maximum changed to 50,000




This command allows the decimal point to be positioned anywhere between the most and least significant digits. To check the current position, issue the DP command without any additional parameters. To change the decimal point position, issue the CE command with the current TAC value and then DP and the new setting. See table below.

DP Set decimal point position


CE

DP

DP_0

CE_17

E+00017 (example)

P+00002

OK

OK


Decimal point is set to 2 places (xxx.xx)

Decimal point set to no places (xxxxx)


This command sets the calibration zero point which is a reference point for all weight calculations (TAC protected). To set a new calibration zero, issue the CE command with the current TAC value and then CZ (when there is no load applied). See table below. Factory default ~ 0mV/V input signal

CZ Set the calibration zero point


CE E+00017 (example) Current TAC value is 17

CE_17 OK Calibration commands enabled

CZ OK New zero point saved

DS Set output reading step size

This command allows you to set different output reading step sizes.10, 20, 50, 100, and 200. Factory default value DS = 1. For example, if the step size is set to 2, then the output value will go up or down in 2s. To check the current step size, issue the DS command without any additional parameters. To change the value of DS, issue the CE command with the current TAC value and then DS and the new setting. See table below.

Permitted values are 1, 2, 5,

In multi range / multi interval applications DS will define the step size in the lowest range / interval. The higher ranges / intervals will use the next step size from the list of allowable step sizes. Factory default setting DS =1.


CE

DS

DS_50

CE_17

E+00017 (example)

S+00002

OK

OK


Display step size is set to 2

Display step size changed to 50


This command allows you to select multi range or multi interval.0 = Multi interval and 1 = Multi range. Factory default value 0. To check the current setting, issue the MR command without any additional parameters. To change the value of MR, issue the CE command with the current TAC value and then MR and the new setting. See table below.

MR Set Multi Range or Multi Interval


CE

MR

MR_1

CE_17

E+00017 (example)

M+00000

OK

OK


Multi Interval is selected

Multi Range is selected




Note: TAC represents the Traceable Access Code (calibration counter) which increments every time new calibration data is stored. Calibration values are only stored in EEPROM when the CS command is issued (see CS command on Page 23)

With this command you can either read the current TAC value or enable a calibration command.check the current TAC value issue the command without any additional parameters. To enable a calibration command, issue the CE command with the current TAC value. See table below.

To

This command MUST be issued PRIOR to any attempt to change calibration parameters such as CZ, CG etc. In legal for trade applications the TAC value can be used to check if any critical parameters have been changed without re-verification. After each calibration the TAC counter increases by 1.

CE TAC counter reading


CE

CE_17

E+00017 (example)

OK



5.2 Calibration Commands CE, CM n, CI, MR, DS, DP, CZ, CG, ZT, FD, IZ, ZR, ZI, WT, CS, TM, TN

This command sets the maximum output value in interval or range n (1<=n<=3).of CM n are between 1 and 999,999.. To check the current value issue the CM n command without any additional parameters. To change the value of CM n, issue the CE command with the current TAC value and then CM n and the new setting. See table below.

Permitted values

The value of CM n will determine the point at which the output will change to “oooooo” signifying over-range. Factory default value CM 1 = 999999, CM 2 = 0, CM 3 = 0

CM n Set maximum output value

This command sets the minimum output value.Factory default value CI = -9 for approved applications. To check the current value issue the CI command without any additional parameters. To change the value of CI, issue the CE command with the current TAC value and then CI and the new setting. See table below.

Permitted values are between 0 and -999,999.

CI Set minimum output value


CE

CI

CI_-10000

CE_17

E+00017 (example)

I-000009

OK

OK


Current output minimum is set to -9

Output minimum changed to -10,000


The value of CM will determine the point at which the output will change to “uuuuuuu” signifying under-range.


CE

CM_1

CM_1_50000

CE_17

E+00017 (example)

M+30000

OK

OK


Current output maximum is set to 30,000

Output maximum changed to 50,000




This command allows the decimal point to be positioned anywhere between the most and least significant digits. To check the current position, issue the DP command without any additional parameters. To change the decimal point position, issue the CE command with the current TAC value and then DP and the new setting. See table below.

DP Set decimal point position


CE

DP

DP_0

CE_17

E+00017 (example)

P+00002

OK

OK


Decimal point is set to 2 places (xxx.xx)

Decimal point set to no places (xxxxx)


This command sets the calibration zero point which is a reference point for all weight calculations (TAC protected). To set a new calibration zero, issue the CE command with the current TAC value and then CZ (when there is no load applied). See table below. Factory default ~ 0mV/V input signal

CZ Set the calibration zero point




CZ OK New zero point saved

DS Set output reading step size

This command allows you to set different output reading step sizes.10, 20, 50, 100, and 200. Factory default value DS = 1. For example, if the step size is set to 2, then the output value will go up or down in 2s. To check the current step size, issue the DS command without any additional parameters. To change the value of DS, issue the CE command with the current TAC value and then DS and the new setting. See table below.

Permitted values are 1, 2, 5,

In multi range / multi interval applications DS will define the step size in the lowest range / interval. The higher ranges / intervals will use the next step size from the list of allowable step sizes. Factory default setting DS =1.


CE

DS

DS_50

CE_17

E+00017 (example)

S+00002

OK

OK


Display step size is set to 2

Display step size changed to 50


This command allows you to select multi range or multi interval.0 = Multi interval and 1 = Multi range. Factory default value 0. To check the current setting, issue the MR command without any additional parameters. To change the value of MR, issue the CE command with the current TAC value and then MR and the new setting. See table below.

MR Set Multi Range or Multi Interval


CE

MR

MR_1

CE_17

E+00017 (example)

M+00000

OK

OK


Multi Interval is selected

Multi Range is selected





CE

IZ

CE_17

E+00017 (example)

OK

OK


Calibration Zero Adjusted


This command is used to adjust the calibration zero point after calibration has been complete. It allows you to set a new zero without having to redo the span calibration. To set a new calibration zero, issue the CE command with the current TAC value and then IZ. See table below.

IZ Adjust Calibration Zero Point

For the best system performance, calibrate the gain (span) as near to the display maximum (CM) as possible. A minimum calibration load of at least 20% is recommended. Factory default calibration gain setting 200000 counts = 2.0000 mV/V input signal. Permitted values 0 - 999999

This command sets the calibration span or gain which is a reference point for all weight calculations (TAC protected).To check the current gain calibration value, issue the CG command without any additional parameters. To change the calibration gain value, issue the CE command with the current TAC value and then CG (with the equivalent load applied). See table below.

CG Set calibration gain (Span)


CE

CG

CG_15000

CE_17

E+00017 (example)

G+10000

OK

OK


Calibration gain set at 10000 counts

Calibration gain set to15000 counts


This command sets the zero tracking band in divisions. issue the ZT command without any additional parameters. To change the zero tracking band, issue the CE command with the current TAC value and then ZT followed by the new setting.

To check the current zero tracking band,

ZT Zero tracking band


CE

ZT

ZT_2

CE_17

E+00017 (example)

Z+00001

OK

OK


Zero tracking band ± 0.5 divisions

Zero tracking band changed to ± 1 division


Zero tracking will only be performed on values within the zero track band, at a rate of 0.4 d per second where d = display set size (see DS command). The zero will only be tracked if it is within the zero track range. See ZR command. If ZT is set to 0, zero tracking is turned off. Factory default: ZT = 0.

This command restores the LDU back to the original factory settings. The data will be written back into EEPROM and the TAC will be incremented by 1. Please note: All calibration and set up data will be lost if the FD command is issued !

FD Factory default settings




FD OK Factory default settings restored


CE

WT

WT_1

CE_17

E+00017 (example)

W+00005

OK

OK


Warm up time set to 5 seconds

Warm up time changed to 1 second


This command sets the warm up time between 0 and 65535 seconds. The warm up time is the period after power on when the output value will be set to ‘uuuuuu’ to avoid false readings during the initial stabilisation period. To check the current value, issue the WT command without any additional parameters. To change the value, issue the CE command with the current TAC value and then WT followed by the new value. See table below. Default value 0.

WT Warm Up Time


This command sets the range in divisions, within which the unit can be zeroed. current value, issue the ZR command without any additional parameters. To change the value, issue the CE command with the current TAC value and then ZR followed by the new setting.

To check the

ZR Zero Range


CE

ZR

ZR_1

CE_17

E+00017 (example)

R+00000

OK

OK


Zero range 0 divisions (default)

Zero range changed to 1 division



This command sets an initial zero range in divisions. If ZI is set to 0 (default value) an initial zero on power up is not performed. If ZI is set to something other than zero, the device will automatically perform a set zero on power up provided that the weight value is stable (within the No motion parameters) and the zero is within the ZI range. To check the current value, issue the ZI command without any additional parameters. To change the value, issue the CE command with the current TAC value and then ZI followed by the new value. See table below.

on power up

ZI Initial Zero Range


CE

ZI

ZI_1

CE_17

E+00017 (example)

R+00005

OK

OK


Initial Zero range 5 divisions

Initial Zero range changed to 1division


The CS command saves all calibration group values as set by CZ, CG, CM, DS, DP, ZT, LC and LN. To do this issue the CE command with the current TAC code followed by CS.

This command stores the calibration values in EEPROM and causes the TAC code to be incremented by 1. If the CS command is not issued and the power to the LDU fails or is turned off, all changes to the calibration values will be lost.

CS Save the calibration values




CS OK Calibration values stored

TM Set Tare Mode

This command sets the tare mode to be compatible with R76 (TM = 1 default).

There are four possible settings (TM = 0 to 3). See table below. Clearing of preset tare value when returning to Range 0 refers to multi-range applications.

To check the current tare mode, issue the TM command without any additional parameters. To change the tare mode, issue the CE command with the current TAC value and then TM followed by the new setting.

The tare mode value is saved using the CS command


CE

TM

TM_0

CE_17

E+00017 (example)

T+001

OK

OK


Tare Mode set to 1 (default)

Tare Mode changed to 0






TN Tare Mode Non Volatile

This command sets the tare mode to be either volatile (TN = 0 default) or non-volatile (TN =1). If set to non-volatile every set/clear tare will write the tare value directly to the EEPROM which is remembered even if the power fails. To check the current tare mode, issue the TN command without any additional parameters. To change the tare mode, issue the CE command with the current TAC value and then TN followed by the new setting. The tare mode non volatile value is saved using the CS command


CE

TN

TN_1

CE_17

E+00017 (example)

T+000

OK

OK





The motion detection facility prevents certain functions from being performed if the weight value is unstable or ‘in-motion’.This ensures that a new value cannot be set when the weight value is varying greatly over a short period of time. For a ‘no-motion’ or ‘stable’ condition to be achieved, the weight signal must not vary by more than NR divisions over the time period NT. If the weight signal is stable, the relevant bit of the ‘Info status’ (IS) response will be set.

The following functions are disabled if motion is detected: Calibrate Zero (CZ), Calibrate Gain (CG), Set Zero (SZ), Set Tare (ST) and Set Preset Tare (SP)

5.4 Motion detection commands - NR, NT

This command sets the range within which the weight signal can vary and still be considered ‘stable’. Permitted values are between 0 and 65535. To check the current value, issue the NR command without any additional parameters. To change the value of NR, issue the NR command with the new setting. See table below. To save this change to EEPROM use the WP command.

With NR = 2, the weight signal can vary no more than ± 2 d, in the time period NT in order to be considered stable. Factory default : NR =1. If NR is set to 0 the no motion band will be set to 0.25 d where d = the display step size DS.

NR No motion range


NR R+00010 No motion range set to 10 d

NR_2 OK No motion range changed to 2 d

WP OK Write parameter to EEPROM

This command sets the time (in milliseconds) over which the weight signal is checked to see if it is ‘stable’ or has ‘no-motion’. The weight signal has to vary by less than NR divisions over the time period NT, to be considered ‘stable’. Permitted values are between 0 and 65535. To check the current value, issue the NT command without any additional parameters. To change the value of NT, issue the NT command with the new setting. See table below. To save this change to EEPROM use the WP command.

With NT = 500, the weight signal can vary no more than ± NR divisions, in the 500 ms in order to be considered stable. Factory default : NT = 1000 milliseconds.

NT No motion time


NT T+01000 No motion time set to 1000 ms

NT_500 OK No motion time changed to 500 ms


Parameter

0

1

2

3

Allow Tare of NegativeValues

YES

NO

YES

NO

Clear preset tare when returned to Range 0

YES

YES

NO

NO

TM Set Tare Mode

This command sets the tare mode to be compatible with R76 (TM = 1 default).

There are four possible settings (TM = 0 to 3). See table below. Clearing of preset tare value when returning to Range 0 refers to multi-range applications.

To check the current tare mode, issue the TM command without any additional parameters. To change the tare mode, issue the CE command with the current TAC value and then TM followed by the new setting.

The tare mode value is saved using the CS command


CE

TM

TM_0

CE_17

E+00017 (example)

T+001

OK

OK









TN Tare Mode Non Volatile

This command sets the tare mode to be either volatile (TN = 0 default) or non-volatile (TN =1). If set to non-volatile every set/clear tare will write the tare value directly to the EEPROM which is remembered even if the power fails. To check the current tare mode, issue the TN command without any additional parameters. To change the tare mode, issue the CE command with the current TAC value and then TN followed by the new setting. The tare mode non volatile value is saved using the CS command


CE

TN

TN_1

CE_17

E+00017 (example)

T+000

OK

OK





The motion detection facility prevents certain functions from being performed if the weight value is unstable or ‘in-motion’.This ensures that a new value cannot be set when the weight value is varying greatly over a short period of time. For a ‘no-motion’ or ‘stable’ condition to be achieved, the weight signal must not vary by more than NR divisions over the time period NT. If the weight signal is stable, the relevant bit of the ‘Info status’ (IS) response will be set.

The following functions are disabled if motion is detected: Calibrate Zero (CZ), Calibrate Gain (CG), Set Zero (SZ), Set Tare (ST) and Set Preset Tare (SP)

5.4 Motion detection commands - NR, NT

This command sets the range within which the weight signal can vary and still be considered ‘stable’. Permitted values are between 0 and 65535. To check the current value, issue the NR command without any additional parameters. To change the value of NR, issue the NR command with the new setting. See table below. To save this change to EEPROM use the WP command.

With NR = 2, the weight signal can vary no more than ± 2 d, in the time period NT in order to be considered stable. Factory default : NR =1. If NR is set to 0 the no motion band will be set to 0.25 d where d = the display step size DS.

NR No motion range


NR R+00010 No motion range set to 10 d

NR_2 OK No motion range changed to 2 d


This command sets the time (in milliseconds) over which the weight signal is checked to see if it is ‘stable’ or has ‘no-motion’. The weight signal has to vary by less than NR divisions over the time period NT, to be considered ‘stable’. Permitted values are between 0 and 65535. To check the current value, issue the NT command without any additional parameters. To change the value of NT, issue the NT command with the new setting. See table below. To save this change to EEPROM use the WP command.

With NT = 500, the weight signal can vary no more than ± NR divisions, in the 500 ms in order to be considered stable. Factory default : NT = 1000 milliseconds.

NT No motion time


NT T+01000 No motion time set to 1000 ms

NT_500 OK No motion time changed to 500 ms


Parameter

0

1

2

3

Allow Tare of NegativeValues

YES

NO

YES

NO

Clear preset tare when returned to Range 0

YES

YES

NO

NO



Using the commands FM and FL, a digital filter type and strength can be set which will eliminate most unwanted disturbances. Please note that these filters are positioned immediately after the A/D converter and therefore affect all aspects of the weighing operation.

5.5 Filter setting commands - FM, FL, UR

The digital IIR filter works as a 2nd order low pass filter with a Gaussian characteristic damping at 40dB/decade. This gives a slower response to a step input with little or no overshoot. See table - Mode 0. For this filter mode, the update rate is not affected by the filter level.

The digital FIR filter also works as a low pass filter which has a quick response with some overshoot. For damping characteristics see table - Mode1. With this filter mode the update rate is dependant on the filter level

This command allows you to select the filter mode. Permitted values are 0 (IIR) or 1 (FIR). To check the current setting, issue the FM command without any additional parameters. To change the FM setting , issue the FM command with the new setting. See table below. To save this change to EEPROM use the WP command. Factory default FM = 0 (IIR)

FM Filter mode FIR / IIR


FM F+00001 Filter mode set to FIR

FM_0 OK Filter mode changed to IIR


If FL= 0 is selected in either filter mode 0 or 1 , the digital filter will be disabled

This command allows you to select the filter level or cut off frequency. Permitted values are between 0 to 8. To check the current setting, issue the FL command without any additional parameters. To change the FL setting , issue the FL command with the new setting. See table below. To save this change to EEPROM use the WP command. Factory default FL = 3

FL Filter Level (Cut off frequency)


FL F+00003 Filter level set to 3

FL_1 OK Filter level changed to 1


Mode 0 Characteristic (IIR-Filter)

FLSettling time to 0.1%

(ms)3dB Cut-off frequency

(Hz)Damping @300Hz

(dB)Update-rate(samples/s)

1 55 18 57 600

2 122 8 78 600

3 242 4 96 600

4 322 3 104 600

5 482 2 114 600

6 963 1 132 600

7 1923 0.5 149 600

8 3847 0.25 164 600

Mode 1 Characteristic (FIR-Filter)

FL

Settling timeto 0.1%

(ms)

3dB Cut-off

(Hz)

20dBdamping atfrequency

(Hz)


(Hz)

Damping inthe stopband

(dB)

Stopband

(Hz)

Update rate

(samples/s)

1 47 19.7 48 64 >90 >80 600

2 93 9.8 24 32 >90 >40 300

3 140 6.5 16 21 >90 >26 200

4 187 4.9 12 16 >90 >20 150

5 233 3.9 10 13 >90 >16 120

6 280 3.2 8 11 >90 >13 100

7 327 2.8 7 9 >90 >11 85.7

8 373 2.5 6 8 >90 >10 75



This command defines how many of the measurements from the preceding IIR or FIR filter are used to calculate an average. Permitted values are between 0 and 7. See table below.

To check the current setting issue the UR command without any additional parameters. To change the setting issue the UR command with the additional parameter. See example below. Default value 0. Remember to save any changes to this parameter using the WP command.

UR Set the update rate


UR

UR_4

U+00001

OK

Average calculated from 2 samples

Average will be calculated from 16 samples.

UR

SAMPLES

0

1

1

2

2

4

3

8

4

16

5

32

6

64

7

128



Using the commands FM and FL, a digital filter type and strength can be set which will eliminate most unwanted disturbances. Please note that these filters are positioned immediately after the A/D converter and therefore affect all aspects of the weighing operation.

5.5 Filter setting commands - FM, FL, UR

The digital IIR filter works as a 2nd order low pass filter with a Gaussian characteristic damping at 40dB/decade. This gives a slower response to a step input with little or no overshoot. See table - Mode 0. For this filter mode, the update rate is not affected by the filter level.

The digital FIR filter also works as a low pass filter which has a quick response with some overshoot. For damping characteristics see table - Mode1. With this filter mode the update rate is dependant on the filter level

This command allows you to select the filter mode. Permitted values are 0 (IIR) or 1 (FIR). To check the current setting, issue the FM command without any additional parameters. To change the FM setting , issue the FM command with the new setting. See table below. To save this change to EEPROM use the WP command. Factory default FM = 0 (IIR)

FM Filter mode FIR / IIR


FM F+00001 Filter mode set to FIR

FM_0 OK Filter mode changed to IIR


If FL= 0 is selected in either filter mode 0 or 1 , the digital filter will be disabled

This command allows you to select the filter level or cut off frequency. Permitted values are between 0 to 8. To check the current setting, issue the FL command without any additional parameters. To change the FL setting , issue the FL command with the new setting. See table below. To save this change to EEPROM use the WP command. Factory default FL = 3

FL Filter Level (Cut off frequency)


FL F+00003 Filter level set to 3

FL_1 OK Filter level changed to 1


Mode 0 Characteristic (IIR-Filter)

FLSettling time to 0.1%

(ms)3dB Cut-off frequency

(Hz)Damping @300Hz

(dB)Update-rate(samples/s)

1 55 18 57 600

2 122 8 78 600

3 242 4 96 600

4 322 3 104 600

5 482 2 114 600

6 963 1 132 600

7 1923 0.5 149 600

8 3847 0.25 164 600

Mode 1 Characteristic (FIR-Filter)

FL

Settling timeto 0.1%

(ms)

3dB Cut-off

(Hz)


(Hz)


(Hz)

Damping inthe stopband

(dB)

Stopband

(Hz)

Update rate

(samples/s)

1 47 19.7 48 64 >90 >80 600

2 93 9.8 24 32 >90 >40 300

3 140 6.5 16 21 >90 >26 200

4 187 4.9 12 16 >90 >20 150

5 233 3.9 10 13 >90 >16 120

6 280 3.2 8 11 >90 >13 100

7 327 2.8 7 9 >90 >11 85.7

8 373 2.5 6 8 >90 >10 75



This command defines how many of the measurements from the preceding IIR or FIR filter are used to calculate an average. Permitted values are between 0 and 7. See table below.

To check the current setting issue the UR command without any additional parameters. To change the setting issue the UR command with the additional parameter. See example below. Default value 0. Remember to save any changes to this parameter using the WP command.

UR Set the update rate


UR

UR_4

U+00001

OK

Average calculated from 2 samples

Average will be calculated from 16 samples.

UR

SAMPLES

0

1

1

2

2

4

3

8

4

16

5

32

6

64

7

128



The following commands allow you to set and reset zero and (preset) tare values. The zero set during calibration remains the ‘true zero’ but a new ‘current zero’ can be set using the SZ command. If the SZ command is issued and accepted then all weight values will be based in the new ‘current zero’. Please remember that the zero value will be subject to the Zero Tracking function if enabled. If the weight signal is not stable (as defined by the No motion range NR and the No motion time NT) then both the set zero (SZ) and the set (preset) tare (SP & ST) commands will be disabled. Also the set zero (SZ) command is not allowed if the new zero value required and the ‘calibration zero’ differ by more than 2% of the CM value (maximum displayed value) and the ZR value is zero. Larger set zero range can be achieved using the ZR command. See Calibration Commands section 5.2. Also see chapter 8 “Legal for trade” applications

5.6 Set Zero/Tare and reset Zero/Tare commands - SZ, RZ, ST, RT, ZA, SP

This command sets a new “current zero” which is then the basis of all weight values until further updated by the zero tracking function, another SZ command or the “reset zero” command (RZ). If the zero range (ZR) is set to zero, the SZ command will fail (LDU responds with ERR) if the new “current zero” is more than 2% (of the CM value) higher or lower than the “true zero” set during calibration. The 2% range can be increased using the ZR command. The SZ command will also fail if the weight signal is not stable, as defined by the no motion range (NR) and no motion time (NT). If the weight signal is “stable”, the response to the IS (device status) command will show the “signal stable” bit active and the SZ command will be accepted (OK). If the signal stable bit is not active, the SZ command will be rejected and the LDU will respond will ERR (error).

The SZ command is issued without any parameters and will return either the OK or ERR response. If the SZ command is accepted, the LDU responds with OK and the”zero action performed” bit of the device status (IS) response will be active (1).

SZ Set Zero


SZ OK New zero set

This command cancels the SZ command and the zero reading reverts to that set by the CZ command during calibration.

The RZ command is issued without any parameters and will return either the OK or ERR response. If the RZ command is accepted, the LDU responds with OK and the”zero action performed” bit of the device status (IS) response (see page 11) will not be active (0).

RZ Reset Zero point


CZ OK Zero reverts to calibration zero (CZ)

This command will activate the net weighing function by storing the current weight value as a tare.The weight signal must be “stable” within the limits set by the no motion range (NR) and the no motion time (NT) for the set tare command to be accepted and the “signal stable” bit of the device status response (IS) to be active. (1)

ST Set Tare

The ST command is issued without any parameters and will return either the OK or ERR response. If the ST command is accepted, the LDU responds with OK and the”zero action performed” bit of the device status (IS) response will be active (1).


ST OK New tare set



RT Reset tare

The RT command is issued without any parameters and will return either the OK or ERR response. If the RT command is accepted, the LDU will respond with OK and the “tare active” bit of the Device Status (IS) response will be set to 0

This command cancels the tare and returns the weighing into gross mode.


RT OK Tare deactivated

This command sets a new system zero as SZ but using the average over the TI period.

ZA Set System Zero


ZA OK System Zero set to average over period TI

This command will activate the net weighing function by storing a preset weight value as a tare.The weight signal must be “stable” within the limits set by the no motion range (NR) and the no motion time (NT) for the set tare command to be accepted and the “signal stable” bit of the device status response (IS) to be active. (1)

SP Set Preset Tare

If the SP command is issued without any parameters the LDU will return the current preset tare value. To change the SP value, send SP followed by the new SP value. If the SP command is accepted, the LDU responds with OK and the”Tare active” bit of the device status (IS) response will be active (4).


SP T+100 Preset tare set to 100

SP_200 OK Preset tare changed to 200

The following commands “Get” the Gross, Net, Tare and ADC sample values from the LDU.

5.7 Output commands GG, GN, GT, GS, GW, GA, GL, OF

This command gets the gross weight value.

GG Get Gross weight value


GG G+01.100 Gross weight value = 1.100 divisions

This command gets the net weight value.

GN Get Net weight value


GN N+01.000 Net weight value = 1.000 divisions

This command gets the tare weight value.

In a multi-range application, optional parameters can be added to the command such as GT 1, GT 2 or GT 3 to make the tare value available rounded to the division size of the corresponding range.

GT Get Tare value


GT T+0.100 Tare value = 0.100 divisions

This command gets the actual Analogue to Digital Converter (ADC) value. This can be useful during development or when calibrating to see how much of the ADC range is being used.

For service applications it may be helpful to note the value of ADC at no load and full load.

GS Get ADC sample value


GS S+125785 ADC value = 125785 counts

GW Get the ‘Long’ weight value

This command gets the ‘long’ weight value. The GW command is issued without any parameters and the response is a single string in the format W+00100+011005109 which contains the current net weight, the current gross weight, the status values and a checksum. The first two sections of the returned string contains the net weight and the gross weight values followed by two hexadecimal characters which represent two bitmapped status indicators. The last two hexadecimal characters represent the checksum, which is the inverse of the sum of all the ASCII values of the string, not including the checksum characters.

First bitmapped binary value: Second bitmapped binary value:

1 not used 1 Signal stable

2 not used 2 Zero action performed

4 Output 0 active 4 Tare active

8 Output 1 active 8 not used

Leading charactersignifies responseto GW command

Net WeightExcluding Decimal point

Gross WeightExcluding Decimal point

First bitmapped binary value

Second bitmapped binary value Checksum

W +00100 +01100 5 1 09





The checksum is derived as follows:-

a) Add together the ASCII values of all 15 characters in the stringb) Convert the decimal result to hexadecimal.c) Remove the most significant digit from the hexadecimal resultd) Invert the remaining hexadecimal valuee) Convert the hexadecimal value to characters.

Please note that during the period after the measuring cycle has been triggered but before the value of GA has been updated, the GA command will return a value 99999, See check weighing timing diagram on page 18. Also see the SA command under the Auto Transmit command section on page 33.


GA Get Average



GL Get the ‘Long’ weight values

This command gets the ‘long’ weight values - the current average, gross and status values. The GL command is issued without any parameters will return the average weight, the gross weight and the status and checksum values all combined in one single string in the format L+00100+01100010F. The first two sections of the returned string contains the average weight and the gross weight values followed by two hexadecimal characters which represent two bitmapped status indicators. The last two hexadecimal characters represent the checksum, which is the inverse of the sum of all the ASCII values of the string, not including the checksum characters. See the GW command for more details.

The following commands allow the Gross, Net, Average and ‘Long’ weight values to be transmitted continuously. Transmission will start as soon as the relevant command has been received and will continue until another valid command is accepted by the LDU. The data output rate will depend on the baud rate being used e.g. with a baud rate of 9600 approximately 100 readings per second can be transmitted.

Note : The auto-transmit commands will only work if the LDU has been set to full duplex [DX=1]

5.8 Auto-transmit commands SG, SN, SA, SW, SL, SX

SG Send the Gross weight value continuously


SG G+01.100 Gross weight value = 1.100 divisions

SN Send the Net weight value continuously


SN N+01.000 Net weight value = 1.000 divisions

Issuing the SA command, the LDU returns an “OK”. It is then primed ready to automatically send the new average weight value when available. The LDU then wait for a trigger signal. As soon as the trigger signal is received the LDU immediately sends “A+99999” indicating that the measuring cycle has started. The value “A+9999” indicates to the host system that the Average Weight value is not valid and should not be used. After the Start Delay (SD) and Measuring Time (MT) have elapsed the new Average Weight is sent. The cycle is repeated each time the trigger signal is received. Thus the Average Weight is automatically sent to the host when a new value is available.

SA Send Average Weight


SA OK LDU is now waiting for a trigger signal

(TRIGGER) A+99999

A+1.1000

Measuring cycle started wait for Av. Weight

Average Weight = 1.1000

(TRIGGER) A+99999

A+1.1500






SW Send the ‘Long’ weight value continuously

This command sends the ‘long’ weight value continuously. The SW command is issued without any parameters and the unit continually returns a string in the format W+00100+011005109 which contains the current net weight, the current gross weight, the status values and a checksum. The first two sections of the returned string contains the net weight and the gross weight values followed by two hexadecimal characters which represent two bitmapped status indicators. The last two hexadecimal characters represent the checksum, which is the inverse of the sum of all the ASCII values of the string, not including the checksum characters. See the GW command under section 5.7 for further details. Please note that the decimal point information is not transmitted.


Use the OF command to put range information into the weight result string and or to put a decimal point into the ‘long’ weight strings.

OF Output Format

Parameter

0

1

2

3

Range Information

NO

YES

NO

YES

Decimal Point in GW/GL

NO

NO

YES

YES


CE

OF

OF_3

CE_17

E+00017 (example)

F_0

OK

OK


Current OF setting 0

OF setting changed to 3


To check the current value , issue the OF command without any additional parameters.. To change the value of OF, issue the CE command with the current TAC value and then OF and the new setting.


The following commands allow the Gross, Net, Average and ‘Long’ weight values to be transmitted continuously. Transmission will start as soon as the relevant command has been received and will continue until another valid command is accepted by the LDU. The data output rate will depend on the baud rate being used e.g. with a baud rate of 9600 approximately 100 readings per second can be transmitted.

Note : The auto-transmit commands will only work if the LDU has been set to full duplex [DX=1]

5.8 Auto-transmit commands SG, SN, SA, SW, SL, SX

SG Send the Gross weight value continuously


SG G+01.100 Gross weight value = 1.100 divisions

SN Send the Net weight value continuously


SN N+01.000 Net weight value = 1.000 divisions

Issuing the SA command, the LDU returns an “OK”. It is then primed ready to automatically send the new average weight value when available. The LDU then wait for a trigger signal. As soon as the trigger signal is received the LDU immediately sends “A+99999” indicating that the measuring cycle has started. The value “A+9999” indicates to the host system that the Average Weight value is not valid and should not be used. After the Start Delay (SD) and Measuring Time (MT) have elapsed the new Average Weight is sent. The cycle is repeated each time the trigger signal is received. Thus the Average Weight is automatically sent to the host when a new value is available.

SA Send Average Weight


SA OK LDU is now waiting for a trigger signal

(TRIGGER) A+99999

A+1.1000



(TRIGGER) A+99999

A+1.1500






SW Send the ‘Long’ weight value continuously

This command sends the ‘long’ weight value continuously. The SW command is issued without any parameters and the unit continually returns a string in the format W+00100+011005109 which contains the current net weight, the current gross weight, the status values and a checksum. The first two sections of the returned string contains the net weight and the gross weight values followed by two hexadecimal characters which represent two bitmapped status indicators. The last two hexadecimal characters represent the checksum, which is the inverse of the sum of all the ASCII values of the string, not including the checksum characters. See the GW command under section 5.7 for further details. Please note that the decimal point information is not transmitted.


Use the OF command to put range information into the weight result string and or to put a decimal point into the ‘long’ weight strings.

OF Output Format

Parameter

0

1

2

3

Range Information

NO

YES

NO

YES

Decimal Point in GW/GL

NO

NO

YES

YES


CE

OF

OF_3

CE_17

E+00017 (example)

F_0

OK

OK


Current OF setting 0

OF setting changed to 3


To check the current value , issue the OF command without any additional parameters.. To change the value of OF, issue the CE command with the current TAC value and then OF and the new setting.


The LDU78.1 has 2 independent logic inputs and 2 independent logic outputs. The inputs and outputs can be configured and controlled completely via the LDU. The logic inputs can be read directly by the host application and the 2 logic outputs have

he logic outputs are usually controlled internally via the setpoint commands but can be configured to be controlled externally by using the IM command.

The following group of commands allows the status of the 2 logic inputs to be read or modified and the logic outputs to be configured for internal or external control.

The use of the setpoint commands (Sn, Hn, An) are explained in the following chapter 5.10

additional control features which allow the user total control over the configuration and action of each output channel. T

5.9 Commands for external I/O control - IN, IO, IM

With this command you can read the status of the two logic outputs. The outputs are normally internally controlled by the setpoint values (See section 5.10). The outputs can however be controlled by the host system if they have been enabled by the IM command. If the IO command is issued without any parameters the response shows the status of the logic outputs in the form of a four digit code where 0 = false and 1 = true (outputs are normally open, open drain MOSFETs), the least significant bit corresponding to Output 0 etc.

IO Read/Modify the status of the output channels

This command is sent without any parameters and reads the status of the two logic inputs. response is in the form of a 4 digit code where 0= false and1 = true (inputs are active ‘high’), the least significant bit corresponding to logic input 0 etc .

The

IN Read the status of the two logic inputs


IN IN:0001

IN:0010

IN:0011

Input 0 active

Input 1 activeIN

IN Input 0 & Input 1 active

Request


IO IO:0001

IO:0010

IO:0011

Output 0 active

Output 1 activeIO

IO Output 0 & Output 1 active

(continues on the next page)


Page 35 LDU78.1 Manual Issue 1g LDU78.1 Manual Issue 1g


SL Send the ‘Long’ weight value continuously

This command sends the ‘long’ weight value continuously. The SL command is issued without any parameters and the unit continually returns a string in the format L+00100+01100010F which contains the current average weight, the current gross weight, the status values and a checksum. The first two sections of the returned string contains the average weight and the gross weight values followed by two hexadecimal characters which represent two bitmapped status indicators. The last two hexadecimal characters represent the checksum, which is the inverse of the sum of all the ASCII values of the string, not including the checksum characters. See the GL command under section 5.7 for further details. Please note that the decimal point information is not transmitted.

SX Send the ADC Sample value continuously

This command send the ADC sample value continuously. The SX command is issued without any parameters and the unit then continually returns the ADC sample value.

The LDU78.1 has 2 independent logic inputs and 2 independent logic outputs. The inputs and outputs can be configured and controlled completely via the LDU. The logic inputs can be read directly by the host application and the 2 logic outputs have

he logic outputs are usually controlled internally via the setpoint commands but can be configured to be controlled externally by using the IM command.

The following group of commands allows the status of the 2 logic inputs to be read or modified and the logic outputs to be configured for internal or external control.

The use of the setpoint commands (Sn, Hn, An) are explained in the following chapter 5.10

additional control features which allow the user total control over the configuration and action of each output channel. T

5.9 Commands for external I/O control - IN, IO, IM

With this command you can read the status of the two logic outputs. The outputs are normally internally controlled by the setpoint values (See section 5.10). The outputs can however be controlled by the host system if they have been enabled by the IM command. If the IO command is issued without any parameters the response shows the status of the logic outputs in the form of a four digit code where 0 = false and 1 = true (outputs are normally open, open drain MOSFETs), the least significant bit corresponding to Output 0 etc.

IO Read/Modify the status of the output channels

This command is sent without any parameters and reads the status of the two logic inputs. response is in the form of a 4 digit code where 0= false and1 = true (inputs are active ‘high’), the least significant bit corresponding to logic input 0 etc .

The

IN Read the status of the two logic inputs


IN IN:0001

IN:0010

IN:0011

Input 0 active

Input 1 activeIN

IN Input 0 & Input 1 active

Request


IO IO:0001

IO:0010

IO:0011

Output 0 active

Output 1 activeIO

IO Output 0 & Output 1 active

(continues on the next page)


LDU78.1 Manual Issue 1gPage 34 LDU78.1 Manual Issue 1g


SL Send the ‘Long’ weight value continuously

This command sends the ‘long’ weight value continuously. The SL command is issued without any parameters and the unit continually returns a string in the format L+00100+01100010F which contains the current average weight, the current gross weight, the status values and a checksum. The first two sections of the returned string contains the average weight and the gross weight values followed by two hexadecimal characters which represent two bitmapped status indicators. The last two hexadecimal characters represent the checksum, which is the inverse of the sum of all the ASCII values of the string, not including the checksum characters. See the GL command under section 5.7 for further details. Please note that the decimal point information is not transmitted.

SX Send the ADC Sample value continuously

This command send the ADC sample value continuously. The SX command is issued without any parameters and the unit then continually returns the ADC sample value.



Request / Setting

5.10 Setpoint Commands - Sn, Hn, An

The LDU78.1 has 2 logic outputs where the status is dependent on the weight value (setpoint). Each logic output can be assigned an independant setpoint value (Sn) with corresponding hysteresis/switch action (Hn) and base (An - switch on the gross or the next weight)

Using the H0 command you can set the hysteresis on the setpoint value and define whether the logic output switches on or off when the setpoint value is reached. The numeric value of H0 sets the hysteresis and the polarity sets the action when the setpoint is reached.

An example of a negative hysteresis of 100 kg (H0= -100) on a setpoint (S0) of 2000 kg (see lines 1 & 2 of the table above):

When the weight is increasing between 0 kg and 2100 kg the logic output is “ON”. Once the weight increases above 2100 kg, the logic output is “OFF”. The logic output will come “ON” again when the weight drops below 2000 kg.

An example of a positive hysteresis of 100 kg (H0= +100) on a setpoint (S0) of 2000 kg (see lines 3 & 4 of the table above):

When the weight is increasing between 0 kg and 1999 kg the logic output is “OFF”. Once the weight increases above 1999 kg, the logic output is “ON”. The logic output will switch “OFF” again when the weight value drops below 1900 kg.

Similarly, to read or change the setpoint value for logic 1, issue the commands as above but substitute S1 instead of S0.

S0 Setpoint value for logic output 0

H0 Hysteresis and switch action for logic output 0

Example


S0

S0_03000

0+01500

OK

Setpoint S0 set to 1500 d

Setpoint S0 changed to 3000 d

Setpoint Hysteresis Output closedLoad

S0 = 2000 kg

S0 = 2000 kg

S0 = 2000 kg

S0 = 2000 kg

decreasing

decreasing

increasing

increasing

H0 = -100kg

H0 = -100kg

H0 = 100kg

H0 = 100kg

2000 kg

1901 kg

0 . . . 2100 kg

Output open

2101 kg

2000 kg

0 . . . 1999 kg

1900 . . . 0 kg

0 . . . 1999 kg

IO Read/Modify the status of the output channels (continued)

Setting

The logic outputs can be controlled by the host application (as opposed to the normal internal setpoints) if they are enabled by the IM command and the appropriate 4 digit code. If this command is issued without any parameters, the response shows which of the logic output are enabled. The response is in the form of a 4 digit code where 0= false and1 = true (inputs are active ‘high’), the least significant bit corresponding to logic input 0 etc .

To enable the logic outputs to be controlled by the host application the IM command must be issued together with a 4 digit code. A “1” bit in the code enables the corresponding logic output to be controlled by the host application using the IO command. A “0” in the code leaves the corresponding logic output controlled by the internal setpoint. Logic output 0 is again the least significant bit.

Note: When reading the status of the logic outputs using the IO command, the setpoint status will be returned regardless of the IM setting. Sending IM 0000 disables the external logic output control.

Factory default:- IM= 0000

IM Control of the logic outputs by the host application

Request


IM IM:0001

IM:0010

IM:0011

Output 0 Enabled

Output 1 EnabledIM

IM Output 0 & Output 1 Enabled


IM_0001 OK

OK

OK

Enable Output 0

Enable Output 1IM_0010

IM_0011 Enable Output 0 & Output 1

Setting

Master ( PC / PLC ) sends LDU XX.X responds Result

IO_0001 OK Output 0 active


IO_0011 OK Output 0+1 active

Please note that the status of the logic outputs is normally determined by the internal setpoint (see section 5.10) and therefore setting the logic output status using the IO command is not allowed unless the IO command followed by the appropriate 4 digit code. For example if IO 0001 was sent to the LDU, the output 0 will be activated (FET conducting).

enabled by the IM command. The status of the outputs can then be changed by issuing





Request / Setting

5.10 Setpoint Commands - Sn, Hn, An

The LDU78.1 has 2 logic outputs where the status is dependent on the weight value (setpoint). Each logic output can be assigned an independant setpoint value (Sn) with corresponding hysteresis/switch action (Hn) and base (An - switch on the gross or the next weight)

Using the H0 command you can set the hysteresis on the setpoint value and define whether the logic output switches on or off when the setpoint value is reached. The numeric value of H0 sets the hysteresis and the polarity sets the action when the setpoint is reached.

An example of a negative hysteresis of 100 kg (H0= -100) on a setpoint (S0) of 2000 kg (see lines 1 & 2 of the table above):

When the weight is increasing between 0 kg and 2100 kg the logic output is “ON”. Once the weight increases above 2100 kg, the logic output is “OFF”. The logic output will come “ON” again when the weight drops below 2000 kg.

An example of a positive hysteresis of 100 kg (H0= +100) on a setpoint (S0) of 2000 kg (see lines 3 & 4 of the table above):

When the weight is increasing between 0 kg and 1999 kg the logic output is “OFF”. Once the weight increases above 1999 kg, the logic output is “ON”. The logic output will switch “OFF” again when the weight value drops below 1900 kg.

Similarly, to read or change the setpoint value for logic 1, issue the commands as above but substitute S1 instead of S0.

S0 Setpoint value for logic output 0

H0 Hysteresis and switch action for logic output 0

Example


S0

S0_03000

0+01500

OK

Setpoint S0 set to 1500 d

Setpoint S0 changed to 3000 d

Setpoint Hysteresis Output closedLoad

S0 = 2000 kg

S0 = 2000 kg

S0 = 2000 kg

S0 = 2000 kg

decreasing

decreasing

increasing

increasing

H0 = -100kg

H0 = -100kg

H0 = 100kg

H0 = 100kg

2000 kg

1901 kg

0 . . . 2100 kg

Output open

2101 kg

2000 kg

0 . . . 1999 kg

1900 . . . 0 kg

0 . . . 1999 kg

IO Read/Modify the status of the output channels (continued)

Setting

The logic outputs can be controlled by the host application (as opposed to the normal internal setpoints) if they are enabled by the IM command and the appropriate 4 digit code. If this command is issued without any parameters, the response shows which of the logic output are enabled. The response is in the form of a 4 digit code where 0= false and1 = true (inputs are active ‘high’), the least significant bit corresponding to logic input 0 etc .

To enable the logic outputs to be controlled by the host application the IM command must be issued together with a 4 digit code. A “1” bit in the code enables the corresponding logic output to be controlled by the host application using the IO command. A “0” in the code leaves the corresponding logic output controlled by the internal setpoint. Logic output 0 is again the least significant bit.

Note: When reading the status of the logic outputs using the IO command, the setpoint status will be returned regardless of the IM setting. Sending IM 0000 disables the external logic output control.

Factory default:- IM= 0000

IM Control of the logic outputs by the host application

Request


IM IM:0001

IM:0010

IM:0011

Output 0 Enabled

Output 1 EnabledIM

IM Output 0 & Output 1 Enabled


IM_0001 OK

OK

OK

Enable Output 0

Enable Output 1IM_0010

IM_0011 Enable Output 0 & Output 1

Setting




IO_0011 OK Output 0+1 active

Please note that the status of the logic outputs is normally determined by the internal setpoint (see section 5.10) and therefore setting the logic output status using the IO command is not allowed unless the IO command followed by the appropriate 4 digit code. For example if IO 0001 was sent to the LDU, the output 0 will be activated (FET conducting).

enabled by the IM command. The status of the outputs can then be changed by issuing





5.11 Communication setup Commands – AD, CL, BR, DX, OP, TD

NOTE: These settings will only take effect after a power on reset (remember to store the settings using the WP command before turning the power off)

With this command, the following Baud rates can be set up: 9600, 19200, 38400, 5760 and 115200 baud.

With this command the communication can be set to half (DX=0) or full (DX=1) duplex.

Factory default: 9600 Baud

Refer to section 2 (page 4) for details of how to carry out an automatic adjustment of the baud rate

Half duplex communication can be used for 2 wire RS485 communication. The auto transmit commands SG, SN and SA will only work if full duplex (DX=1) is selected. Factory default DX=0

Request / Set device address

Setting the device address to 0 will cause the device to be permanently active, listening and responding to every command on the bus without the need for an OP command.

Factory default: Address 0

Refer to section 2 (page 4) for details of how to carry out a manual setting of the address by soldering SW3.

AD Device address setup / request


AD

AD_49

A:000

OK

Address set to 0

Address changed to 49


BR

BR_115200

B:9600

OK

Baud rate set to 9600

Baud rate changed to 115K2 baud


DX

DX_1

X:000

OK

Half duplex set

Communication changed to full duplex

CL Close Device address n

BR Request / Setup Baud Rate

DX Half or full duplex communication


CL_3 OK Device 3 closed



Request / Set base for logic output 0

Setpoint range between ± 1 (minimum) and ± 99999 (maximum) Similarly, to read or change the hysteresis value for logic 1, issue the commands as above but substitute H1 instead of H0.

The A0 command defines the base on which the setpoint acts. If A0 is set to “0” then the setpoint acts on the unfiltered gross weight. So when the unfiltered gross weight reaches the setpoint, the logic output turns on/off. Similarly, if A0 is set to “1” then the setpoint acts on the unfiltered net weight or if A0 is set to “2” then the setpoint acts on the Average Weight (GA).

A0 Request / Set the base for logic output 0

Request / Set Hysteresis value on logic output 0


H0

H0_100

0-00100

OK

Hysteresis on S0 set to -100 kg

Hysteresis on S0 changed to +100 kg

Similarly, to read or change the base for the setpoint of logic 1, issue the commands as above but substitute A1 instead of A0.

NOTE: All changes to the setpoint settings have to be stored in EEPROM using the SS command. See section 5.12


A0

A0_1

0+00000

OK

Setpoint acts on the unfiltered gross weight

Setpoint acts on the unfiltered net weight



5.12 Save calibration, setup and setpoint parameters commands - CS, WP, SS, PI, GI

The setup and calibration parameters can be divided into 3 groups:

Calibration parameters: CZ, CG, DS, DP, ZT etc. are saved by the CS command.

Setup parameters (other than setpoint): FL, FM, NR, NT, BR, AD, DX etc. are saved by the WP command.

Setpoint parameters: S0, S1, H0, H1, A0, A1 are saved by the SS command.

Please note that the calibration parameters can only be saved if the TAC code is known and precedes the CS command. See the CE and CS commands on pages 20 & 23 respectively.

Both the setup parameters and the setpoint parameters are stored in EEPROM using the WP and SS commands respectively.

WP Save the setup parameters

With this command the settings of the Filter (FL, FM), the No-motion (NR, NT) and communication (AD, BR, DX) will be saved in the EEPROM.


WP OK Parameter saved

SS Save the Setpoint setup parameters

With this command the value of the setpoints (S0 & S1), the setpoint hysteresis (H0 & H1) and the setpoint action (A0 & A1) will be saved in the EEPROM.


SS OK Parameter saved

PI Put EEPROM Image

With this command you can download a HEX-INTEL formatted EEPROM image into the LDU. The image contains all stored information except the calibration data. The LDU must have the same firmware type and revision as the source.

GI Get EEPROM Image

With this command you can get a HEX-INTEL formatted EEPROM image from the LDU. The image contains all stored information except the calibration data. The image can be downloaded into any LDU 78.1 as long as it has the same firmware type and revision as this unit..

The PI and GI command must be handled by a host program able to read the hex data from the LDU and write it to a number of other LDUs for “cloning”. These commands are useful if you want to set up a large number of LDUs in the same way e.g. in some kind of production.



Request / Enable device communication

This command, if sent without parameters, requests the address or device number of the device active on the bus. If sent with parameters, this enables the device defined by the parameters.

The requested device acknowledges its readiness and responds to all bus commands until a further OP command arrives with a different device address or a CL command is received.

OP Device communication enable / request


OP

OP_14

O:0003

OK

Device 3 open

Device 14 opened

This command allows to set a delay between the LDU receiving a command and responding. You can set this delay anywhere between 0 and 255 milliseconds.

To read the current Time Delay setting issue the TD command without any parameters. To change the value of Time Delay issue the TD command followed by a space and then the value of the delay required in milliseconds e.g. TD 255 to set the delay to 255 milliseconds.

To save the new Time Delay setting, issue the WP command.

TD Transmit Delay

This command is particularly useful when LDUs are used on a 2 wire RS485 bus where the host PLC is unable to ‘turn around’ the transmit and receive lines quick enough to prevent missing part or all of the answer.

Request / Set Transmit Delay time


TD

TD_1

D:0000

OK

Transmit delay set to 0 milliseconds

Transmit delay changed to 1 millisecond



7 USE IN “APPROVED” APPLICATIONS

The term “approved” applies whenever the weighing application is intended to be used for “legal for trade” weighing - that is, money will change hands according to the weight result. Such applications are bound by the legal metrology regulations of the relevant governments around the world, but most countries will comply with either the relevant ENs (Euro Norms) or the relevant OIML (Organization Internationale de Metrologie Legale) recommendation

The LDU78.1 has been approved as a component for use in weighing systems according to OIML recommendations R76, the highest performance level approved being Class III, 10000 divisions. The approval authority was the Danish Electronics, Light & Acoustic (DELTA) and the approval certificate number is DK0199-R76-10.08. This approval will allow the use in approved weighing throughout Europe and many other countries in the World.

To achieve approval on a particular application, it will be necessary to satisfy the relevant Governmental Trading Standards Authority that the requirements of the various rules and regulations have been satisfied. This task is greatly simplified if the key components of the weighing system, namely the load cells and the weighing indicator or digitiser, are already approved as “components”.

Usually, a discussion with the Weighing Equipment Approvals Officers at the relevant National Weights & Measures Office will then reveal the extent of any pattern testing that may be necessary to ensure compliance.

Restrictions upon usage when in “Approved” applications

A number of performance restrictions must come into force. These restrictions are the number of display divisions, which become limited to 10000 divisions, and the sensitivity per display division, which becomes 0.4uV per division.

Once installed in the application, an “approved” application will require “stamping” by an Officer of the relevant Governmental Trading Standards Department. This certifies the equipment or system as being in accordance to the relevant regulations and within calibration limits.

The Traceable Access Code (TAC)

The user software must then provide a guard against improper access of the calibration commands (see the “Calibration Commands” section). The LDU 78.1 digitiser features the “Traceable Access Code” or TAC method of controlling the access to the calibration commands group. This means that a code is maintained within the device, and is incremented whenever any change to any of the calibration commands is saved.

When performing the “stamping” test, the Trading Standards Officer will make a note of the TAC, and advise the user that any change to this code which occurs prior to the regular re-inspection by the Trading Standards Office, will result in legal prosecution of the user.

The user software is required as a condition of approval, to make the TAC available to the weight display indicator or console, on demand.

6 CALIBRATION PROCEDURE.

Example: setup of zero point, gain and decimal point.


CE E+00017 Request: TAC-counter CE = 17

CE_17 OK Calibration sequence active

Scale no load !

CZ OK System zero point saved


Put calibration weight on (500 g) !

CG_5000 OK Setting span

CG G+05000 Request: span 5000 d


DP_1 OK Setting: decimal point 0000.0


CS OK Save calibration data in EEPROM

The calibration interface features a “TRACEABLE ACCESS CODE” (TAC), which is required for use in “Approved” applications (see section 7, “USE IN APPROVED APPLICATIONS” for more details). This feature also ensures that there is no inadvertent or unauthorized access to the calibration parameters. The following parameters are considered as CALIBRATION commands:

CE Calibration Enable - returns the current TAC value.

CZ Calibrate zero - sets the system zero point

CG Calibrate gain - sets the system gain

CM Calibrate maximum - sets the maximum allowable display value.

DS Display step size - sets the output incremental step size.

DP Display decimal point - sets the position of the output decimal point

ZT Zero track enable.

FD Factory default settings (return to)

CS Calibration save

Zero point, gain and decimal point position were saved in the EEPROM; the calibration counter (TAC) is increased automatically by 1.

The chosen test weight has the value equivalent to 5000 increments. This could be 500 g, 5kg or 5000 kg. We will calibrate with a 500 g weight. The decimal point is set to 1 place using the DP command. So although the CG value (5000) does not contain a decimal place the final result does (500.0).





7 USE IN “APPROVED” APPLICATIONS

The term “approved” applies whenever the weighing application is intended to be used for “legal for trade” weighing - that is, money will change hands according to the weight result. Such applications are bound by the legal metrology regulations of the relevant governments around the world, but most countries will comply with either the relevant ENs (Euro Norms) or the relevant OIML (Organization Internationale de Metrologie Legale) recommendation

The LDU78.1 has been approved as a component for use in weighing systems according to OIML recommendations R76, the highest performance level approved being Class III, 10000 divisions. The approval authority was the Danish Electronics, Light & Acoustic (DELTA) and the approval certificate number is DK0199-R76-10.08. This approval will allow the use in approved weighing throughout Europe and many other countries in the World.

To achieve approval on a particular application, it will be necessary to satisfy the relevant Governmental Trading Standards Authority that the requirements of the various rules and regulations have been satisfied. This task is greatly simplified if the key components of the weighing system, namely the load cells and the weighing indicator or digitiser, are already approved as “components”.

Usually, a discussion with the Weighing Equipment Approvals Officers at the relevant National Weights & Measures Office will then reveal the extent of any pattern testing that may be necessary to ensure compliance.

Restrictions upon usage when in “Approved” applications

A number of performance restrictions must come into force. These restrictions are the number of display divisions, which become limited to 10000 divisions, and the sensitivity per display division, which becomes 0.4uV per division.

Once installed in the application, an “approved” application will require “stamping” by an Officer of the relevant Governmental Trading Standards Department. This certifies the equipment or system as being in accordance to the relevant regulations and within calibration limits.

The Traceable Access Code (TAC)

The user software must then provide a guard against improper access of the calibration commands (see the “Calibration Commands” section). The LDU 78.1 digitiser features the “Traceable Access Code” or TAC method of controlling the access to the calibration commands group. This means that a code is maintained within the device, and is incremented whenever any change to any of the calibration commands is saved.

When performing the “stamping” test, the Trading Standards Officer will make a note of the TAC, and advise the user that any change to this code which occurs prior to the regular re-inspection by the Trading Standards Office, will result in legal prosecution of the user.

The user software is required as a condition of approval, to make the TAC available to the weight display indicator or console, on demand.

6 CALIBRATION PROCEDURE.

Example: setup of zero point, gain and decimal point.


CE E+00017 Request: TAC-counter CE = 17


Scale no load !

CZ OK System zero point saved


Put calibration weight on (500 g) !

CG_5000 OK Setting span

CG G+05000 Request: span 5000 d


DP_1 OK Setting: decimal point 0000.0


CS OK Save calibration data in EEPROM

The calibration interface features a “TRACEABLE ACCESS CODE” (TAC), which is required for use in “Approved” applications (see section 7, “USE IN APPROVED APPLICATIONS” for more details). This feature also ensures that there is no inadvertent or unauthorized access to the calibration parameters. The following parameters are considered as CALIBRATION commands:

CE Calibration Enable - returns the current TAC value.

CZ Calibrate zero - sets the system zero point

CG Calibrate gain - sets the system gain

CM Calibrate maximum - sets the maximum allowable display value.

DS Display step size - sets the output incremental step size.

DP Display decimal point - sets the position of the output decimal point

ZT Zero track enable.

FD Factory default settings (return to)

CS Calibration save

Zero point, gain and decimal point position were saved in the EEPROM; the calibration counter (TAC) is increased automatically by 1.

The chosen test weight has the value equivalent to 5000 increments. This could be 500 g, 5kg or 5000 kg. We will calibrate with a 500 g weight. The decimal point is set to 1 place using the DP command. So although the CG value (5000) does not contain a decimal place the final result does (500.0).





9 UNIT ADAPTOR CONNECTION DETAIL

With UA77.1 (Unit Adaptor with built-in RS422 to RS232 Converter)

External Connections

FunctionUA 77.1 TerminalPin No. LDU78.1

Common Ground (Load cell cable shield)Gnd (Shield)0

Positive Load cell excitation voltage+ Exc (to load cell)1

Positive Load cell sense voltage+ Sen2

Positive Load cell signal voltage+ Inp (to LDU)3

Negative Load cell signal voltage- Inp (to LDU)4

Negative Load cell sense voltage- Sen5

Negative Load cell excitation voltage- Exc (to load cell)6

Common Ground (Load cell cable shield)Gnd 7

Not Connected8

Not Connected9

Receive Data RS232 RxD (RS232)10

RS232 Common GroundGnd (RS232)11


Transmit Data RS232TxD (RS232)13

Logic Input 0 (relative to common ground) 0 In14

Logic Output 0 (relative to common ground)0 Out15

Logic Input 1 (relative to common ground)1 In16


Power Supply 12-24 V DC+ PWR18

Common GroundGnd 19

9.1 UA77.1 Unit Adaptor with built-in RS422 to RS232 converter

R1

R2P2

P1


Zero Adj.R3R4


P2 Span Adj.

R1P1Zero Adj.

R3R4

Exc 67

Gnd

Gnd

Gnd


+0

1

--

0

18


0

1617

1918

151413121110

+++---

NCNC

I I I


LDU 78.1


Dmin = 0.4mV/VSI

TECHNIQUES LIMITED


Tx

GND

Rx

GND

+12 - 24V

Gnd

Fro

m C

om

pute

r o

r PLC



8 SOFTWARE (FIRMWARE) DOWNLOAD

To download new firmware into the LDU XX.X, you will require a Windows PC with an either an RS232 port or a USB port and an RS232 or USB to RS422/485 converter. The solder pad SW5 on the under side of the PCB has to be closed (linked across) before switching on the power. After downloading the new firmware the link has to reopened.

All files required to download new firmware (LduDownload.exe, prog78.a20 & LduXX.a20) must be stored in the same directory. The actual firmware to be downloaded is in the file LduXX.a20. These files will be provided by your local LDU supplier on request.

Remove the power to the LDU XX.X. Link the solder pads SW5 on the back of the LDU XX.X with a solder bridge.Power up the LDU XX.XStart the “LduDownload” program.Press the “Load” button and choose the “LduXX.a20” file Press the “Program” button When the message “Reset LDU before proceeding” appears, switch the LDU off and wait 5 seconds. Re-apply the power and press “OK”The download will now proceed - When the download is complete the “Programming OK” message will be displayed.Switch off the LDU and remove the solder bridge from the SW5 pads on the back of the LDU PCBNow use the DOP program or a terminal program (such as Hyperterminal) to run the Factory Reset command (FD)

Please note that the FD command is TAC protected. You must issue the CE command with the relevant TAC code prior to the FD command otherwise the FD command will fail.

8.1 Firmware update for LDU XX.X series



9 UNIT ADAPTOR CONNECTION DETAIL

With UA77.1 (Unit Adaptor with built-in RS422 to RS232 Converter)







Negative Load cell signal voltage- Inp (to LDU)4




Not Connected8

Not Connected9

Receive Data RS232 RxD (RS232)10



Transmit Data RS232TxD (RS232)13






Common GroundGnd 19

9.1 UA77.1 Unit Adaptor with built-in RS422 to RS232 converter

R1

R2P2

P1


Zero Adj.R3R4


P2 Span Adj.

R1P1Zero Adj.

R3R4

Exc 67

Gnd

Gnd

Gnd


+0

1

--

0

18


0

1617

1918

151413121110

+++---

NCNC

I I I


LDU 78.1


Dmin = 0.4mV/VSI

TECHNIQUES LIMITED


Tx

GND

Rx

GND

+12 - 24V

Gnd

Fro

m C

om

pute

r o

r PLC



8 SOFTWARE (FIRMWARE) DOWNLOAD

To download new firmware into the LDU XX.X, you will require a Windows PC with an either an RS232 port or a USB port and an RS232 or USB to RS422/485 converter. The solder pad SW5 on the under side of the PCB has to be closed (linked across) before switching on the power. After downloading the new firmware the link has to reopened.

All files required to download new firmware (LduDownload.exe, prog78.a20 & LduXX.a20) must be stored in the same directory. The actual firmware to be downloaded is in the file LduXX.a20. These files will be provided by your local LDU supplier on request.

Remove the power to the LDU XX.X. Link the solder pads SW5 on the back of the LDU XX.X with a solder bridge.Power up the LDU XX.XStart the “LduDownload” program.Press the “Load” button and choose the “LduXX.a20” file Press the “Program” button When the message “Reset LDU before proceeding” appears, switch the LDU off and wait 5 seconds. Re-apply the power and press “OK”The download will now proceed - When the download is complete the “Programming OK” message will be displayed.Switch off the LDU and remove the solder bridge from the SW5 pads on the back of the LDU PCBNow use the DOP program or a terminal program (such as Hyperterminal) to run the Factory Reset command (FD)

Please note that the FD command is TAC protected. You must issue the CE command with the relevant TAC code prior to the FD command otherwise the FD command will fail.

8.1 Firmware update for LDU XX.X series



R1

R2P2

P1


Zero Adj.R3R4


P2 Span Adj.

R1P1Zero Adj.

R3R4

Exc 67

Gnd

Gnd

Gnd


+0

1

--

0

18


0

1617

1918

151413121110

+++---

I I I


LDU 78.1


Dmin = 0.4mV/VSI

NCNC

TECHNIQUES LIMITED

www.sensortechniques.comConnect theSignal Groundto the Power Supply Ground

Connect theSignal Groundto the Power Supply Ground

The following example shows how to wire up 2 or more LDU 78.1s in a multi-drop application to an USB port of a PC using a USB to RS422/485 converter. This circuit has been tested and is known to work correctly. The USB to RS422/485 converters can be purchased from Sensor Techniques Limited

10 USB to RS422/485 CONVERTER WIRING (MULTI-DROP)

1 5

6 9Tx +

Rx +

Rx -Screen

Tx -

To USB Port on Computer

R1

R2P2

P1


Zero Adj.R3R4


P2 Span Adj.

R1P1Zero Adj.

R3R4

Exc 67

Gnd

Gnd

Gnd


+0

1

--

0

18


0

1617

1918

151413121110

+++---

I I I


LDU 78.1


Dmin = 0.3mV/VSI

NCNC

TECHNIQUES LIMITED


REAR VIEW OF 9 WAY FEMALE D TYPE CONNECTOR (SOLDER BUCKET)



With UA73.2 (Standard Unit Adaptor)







Negative Load cell signal voltage- Inp (to LDU))4




Not Connected8

Not Connected9

Receive Data + +Rx (RS422)10

Receive Data --Rx (RS422)11

Transmit Data ++Tx (RS422)12

Transmit Data --Tx (RS422)13






Common GroundGnd 19

9.2 UA73.2 Standard Unit Adaptor

R1

R2P2

P1


Zero Adj.R3R4


P2 Span Adj.

R1P1Zero Adj.

R3R4

Exc 67

Gnd

Gnd

Gnd


+0

1

--

0

18


0

1617

1918

151413121110

+++---

NCNC

I I I


LDU 78.1


Dmin = 0.4mV/VSI

TECHNIQUES LIMITED


Tx+

Tx-

Rx+

Rx-

Signal Gnd

+12 - 24V

Gnd

load cell digitizing unit type ldu 78€¦ · command set. so you can connect up to 32 sg...

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